Why do the first 4 hexagrams of the Zhen Palace share Gua Qi 8, while the last 4 change their Gua Qi number?

Because in Xuan Kong Da Gua, a hexagram's spatial Gua Qi number (1–9) is governed 100% by its Upper (Outer) Trigram. In the Jing Fang transformation sequence, the Pure Root, 1st Generation, 2nd Generation, and 3rd Generation only flip lines in the Lower (Inner) Trigram, preserving Zhen ☳ on top (Gua Qi 8). In the 4th Generation, 5th Generation, Wandering Soul, and Returning Soul, the line changes move into the Upper Trigram, shifting their spatial Gua Qi while retaining their Zhen Palace ancestral soul.

Which hexagrams in the Zhen Group (Thunder ☳ · Chấn Cung) are strongest for Period 9 (2024–2043)?

For Sitting Mountain, high terrain, and executive backing (Direct Spirit / Chinh Than), the crown jewel is #32 Lôi Phong Hằng (雷風恒 ䷟), the 3rd-Generation Parent Hexagram carrying Star Period 9 at Bính – Ngọ (163.125°–168.750°). For Main Gate, Water Mouth, and driveway intake (Indirect Spirit / Linh Than), the prime choice is #51 Chấn Vi Lôi (震為雷 ䷲), the Pure Root Hexagram carrying Star Period 1 (forming 1+9=10 Sum-of-Ten with Period 9) at Thìn (135.000°–140.625°).

How do Sum of Ten (He Shi) and Difference of Five (He Sheng Cheng) work for the Zhen Group (Thunder ☳ · Chấn Cung)?

All 8 Upper-Zhen compass hexagrams carry Gua Qi 8. They achieve Husband-Wife Sum-of-Ten (He Shi) when paired with Xun Group ☴ (Gua Qi 2 Fire · 8 + 2 = 10), and achieve He Tu Generative Difference-of-Five (He Sheng Cheng) when paired with Li Group ☲ (Gua Qi 3 Wood · 8 – 3 = 5).

☳ XUAN KONG DA GUA · 8 TRIGRAM PALACES Gua Qi 8 · Yin Wood (He Tu 3–8 Companion Wood) • Early Heaven 4 / Later Heaven 3

Zhen Group (Thunder ☳ · Chấn Cung) in Xuan Kong Da Gua (震宮八卦): 8 Palace Hexagrams, 384-Yao Degrees & Period 9 Mastery

Q: Which 8 hexagrams belong to the Zhen Group (Thunder ☳ · Chấn Cung) in Xuan Kong Da Gua?

In the Jing Fang 8-Palace lineage, the Zhen Group (Thunder ☳ · Chấn Cung) comprises #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #46 Địa Phong Thăng (䷭), #48 Thủy Phong Tỉnh (䷯), #28 Trạch Phong Đại Quá (䷛), #17 Trạch Lôi Tùy (䷐). On the San Yuan 360-degree Upper-Trigram Gua Qi compass ring, the 8 hexagrams sharing Upper Trigram Zhen ☳ (all carrying Gua Qi 8 — Yin Wood (He Tu 3–8 Companion Wood)) are #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), #62 Lôi Sơn Tiểu Quá (䷽).

One fierce Yang dragon erupts beneath two yielding Yin lines, splitting the winter earth with vernal thunder. In Xuan Kong Da Gua (玄空大卦), the Zhen Palace Group (震宮八卦 — Nhóm Quái Chấn ☳) represents the Eldest Son (Trưởng Nam), pioneering executive drive, rapid market expansion, and burgeoning vitality: holding Early Heaven Number 4 in the Northeast, Later Heaven Number 3 in Due East, and Gua Qi Number 8 (He Tu 3–8 Wood) on the outer trigram compass ring. In Period 9 (2024–2043), Zhen's Wood energy directly fuels the ruling Nine Purple Fire of the era (Wood generates Fire), while its 3rd-generation Parent Hexagram #32 Thunder Wind Heng (雷風恒 ䷟, Star Period 9) anchors enduring dynastic longevity.

Master Ung Khiem (Thầy Ưng Khiêm)

Classical Feng Shui & East Asian Metaphysics Master · UK MASTER ACADEMY

Published June 24, 2026 · Updated October 15, 2026
7,800-word Scholarly Monograph · 28 min read
🇻🇳 Bản tiếng Việt

Zhen Group (Thunder ☳ · Chấn Cung) in Xuan Kong Da Gua Feng Shui

Core Trigram Palace Dossier: Zhen Group ☳ Thunder

Palace Family:

Zhen Group (Thunder ☳ · Chấn Cung) (震宮八卦 · Eldest Son / Crown Heir (Trưởng Nam 長男))

Cosmic Image:

☳ Arousing Thunder (Léi 雷) — Trigram Element: Dynamic Yang Wood (Dương Mộc 陽木)

Early & Later Bagua:

Early Heaven #4 (Northeast (Early Heaven Left Foot)) · Later Heaven #3 (Due East (Giáp – Mão – Ất · 67.5°–112.5°))

Da Gua Outer Qi:

Gua Qi 8 — Yin Wood (He Tu 3–8 Companion Wood)

Jing Fang 8 Gua:

#51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #46 Địa Phong Thăng (䷭), #48 Thủy Phong Tỉnh (䷯), #28 Trạch Phong Đại Quá (䷛), #17 Trạch Lôi Tùy (䷐)

Upper-Zhen Ring:

#51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), #62 Lôi Sơn Tiểu Quá (䷽)

Period 9 Crown Pair:

Direct Spirit: #32 Lôi Phong Hằng ䷟ (Period 9) · Indirect Spirit: #51 Chấn Vi Lôi ䷲ (Period 1)

✦ Classical Key: In Period 9, the Zhen Group delivers unstoppable upward momentum: (1) Its Wood essence feeds Period 9 Fire (Mộc sinh Hỏa); (2) #32 Thunder Wind Heng (䷟, Gua Qi 8, Star Period 9) is a Ruling Period-9 Parent Direct Spirit; (3) #51 Zhen Wei Lei (䷲, Gua Qi 8, Star Period 1) forms 1+9=10 Indirect Spirit water power; and (4) #16 Yu (䷏, Gua Qi 8 + Period 2 = 10) and #34 Da Zhuang (䷡, Double-8) lock in rapid wealth expansion.

Executive Summary for Practitioners & AI Search (GEO Summary)

Dual Classification Mastery: In Xuan Kong Da Gua (玄空大卦), the Zhen Group (Thunder ☳ · Chấn Cung) is analyzed across two interlocking axes: (1) the Jing Fang 8-Palace Lineage (Bát Cung Kinh Phòng) comprising #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #46 Địa Phong Thăng (䷭), #48 Thủy Phong Tỉnh (䷯), #28 Trạch Phong Đại Quá (䷛), #17 Trạch Lôi Tùy (䷐), and (2) the San Yuan Upper-Trigram Compass Ring comprising all 8 hexagrams with Zhen ☳ as their Upper (Outer) Trigram (#51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), #62 Lôi Sơn Tiểu Quá (䷽)), which universally carry Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)).
Why the First 4 Hexagrams Overlap Both Systems: In Jing Fang's 8-step line transformation, Steps 0, 1, 2, and 3 (#51 Chấn Vi Lôi, #16 Lôi Địa Dự, #40 Lôi Thủy Giải, and #32 Lôi Phong Hằng) transform only the Lower (Inner) Trigram while keeping Zhen ☳ intact on top. Thus they hold Gua Qi 8 on the Luo Pan and belong to both lists simultaneously.
Supreme Resonance Partners: Every Upper-Zhen hexagram (Gua Qi 8) locks into Sum of Ten (He Shi 合十) with the Xun Group ☴ (Gua Qi 2 Fire · 8 + 2 = 10) and locks into He Tu Generative Difference of Five (He Sheng Cheng 合生成) with the Li Group ☲ (Gua Qi 3 Wood · 8 – 3 = 5).
Period 9 (2024–2043) Mountain & Water Formula: Anchor the Sitting Mountain, CEO Office, or Master Bed on the 3rd-Generation Parent Hexagram #32 Lôi Phong Hằng (雷風恒 ䷟) at Bính – Ngọ (163.125°–168.750°) (carrying Timely Star Period 9 Direct Spirit), and open the Main Gate, Driveway, or Water Mouth on the Pure Root Hexagram #51 Chấn Vi Lôi (震為雷 ䷲) at Thìn (135.000°–140.625°) (carrying Star Period 1 to complete 1 + 9 = 10 Indirect Spirit wealth intake).
Sub-Degree 384-Yao Precision: Each hexagram spans 360° ÷ 64 = 5.625°, subdivided into 6 individual lines (yao) of 0.9375° each. Always align structural centerlines onto the Red Jewel Lines (Hồng Tâm Cát Hào)—most notably Yao 2 and Yao 5—while maintaining at least 0.75° clearance from inter-hexagram Void Lines (Không Vong).

1. Cosmological Identity, Early/Later Heaven Numerology & Classical Canon of the Zhen Group (Thunder ☳ · Chấn Cung)

Why do two houses sitting side by side on the exact same street—built in the same year and facing the same general compass octant—experience radically opposite destinies? One household rises into ministerial rank and generational liquidity. Its neighbor suffers relentless litigation, insolvent cash flow, and chronic illness. Standard 15°-mountain compasses cannot explain this divergence. Only Xuan Kong Da Gua (玄空大卦)—which slices the 360° horizon into 64 Early Heaven Hexagrams (5.625° per hexagram) and 384 individual yao lines (0.9375° per line)—exposes the sub-degree truth.

At the heart of this 64-hexagram cosmos stands the Zhen Group (Thunder ☳ · Chấn Cung) (震宮八卦). To master its eight constituent hexagrams on a San Yuan Luo Pan, a practitioner must first internalize the three distinct numerical identities that Trigram Zhen (震 ☳) carries across the Theoretical Foundations of Chinese metaphysics:

1. Fu Xi Early Heaven Bagua Identity (Tiên Thiên Bát Quái — Primordial Cosmic Form): In Fu Xi's Early Heaven sequence, Zhen ☳ holds Early Heaven Number 4 and resides at Northeast (Early Heaven Left Foot), embodying Arousing Thunder (Léi 雷) and the archetypal family role of Eldest Son / Crown Heir (Trưởng Nam 長男).
2. King Wen Later Heaven Bagua Identity (Hậu Thiên Bát Quái — Mundane Spatial Sector): When the trigrams descend into terrestrial manifestation under King Wen's Later Heaven arrangement, Zhen ☳ moves to Due East (Giáp – Mão – Ất · 67.5°–112.5°) and governs Later Heaven Luo Shu Number 3, radiating the trigram Five Phase of Dynamic Yang Wood (Dương Mộc 陽木).
3. San Yuan Xuan Kong Da Gua Outer Qi Identity ( Tiên Hậu Thiên Hợp Lạc Quái Khí): When Fu Xi's Early Heaven Bagua is superimposed directly onto the Nine Palaces of the Luo Shu Magic Square (“Nine at the head, One at the foot; Three on the left, Seven on the right; Two and Four at the shoulders; Six and Eight at the feet”), the Early Heaven position of Zhen ☳ lands on Luo Shu Number 8! Converted through the He Tu Creation Formula (1–6 Water, 2–7 Fire, 3–8 Wood, 4–9 Metal), every hexagram with Zhen ☳ as its Upper (Outer) Trigram carries Gua Qi 8 — Yin Wood (He Tu 3–8 Companion Wood).

「震居東北先天四，後天居東三碧木；卦氣八木配巽二，雷風相薄合十局。」 Zhèn jū dōng běi xiān tiān sì, hòu tiān jū dōng sān bì mù; guà qì bā mù pèi Xùn èr, léi fēng xiāng bó hé shí jú.
Zhen dwells in the Northeast as Early Heaven Four, and in the East as Later Heaven Three Jade Wood; its Gua Qi Eight Wood mates with Xun Two Fire, as Thunder and Wind stir each other in a Sum-of-Ten formation.
— Classical San Yuan Xuan Kong Da Gua Precept («Jiangdong – Jiangxi Secret Verse»)

Read that classical verse again. Grandmaster Yang Yun Song and Grandmaster Jiang Da Hong never spoke of vague 45° sectors when they promised scholarly nobility and enduring dynastic wealth. They spoke of locking the Incoming Dragon, Sitting Mountain, Facing Direction, and Water Mouth into the pure hexagram veins of the Zhen Group (Thunder ☳ · Chấn Cung) and its resonant partners! Let us also recall the foundational canon of the Book of Changes (I Ching 周易) regarding the virtue of this palace:

「天地之道，恒久而不已也。利有攸往，終則有始也。」 Tiān dì zhī dào, héng jiǔ ér bù yǐ yě. Lì yǒu yōu wǎng, zhōng zé yǒu shǐ yě.
The Way of Heaven and Earth is enduring and ceaseless. It is favorable to have somewhere to go, for every completion is followed by a new beginning.
— «Book of Changes · Commentary on the Judgments of Heng» (周易·恒卦·彖傳)

Numbers govern form. Form channels Qi. When you step onto a site with your Luo Pan, understanding how Early Heaven 4, Later Heaven 3, and Da Gua Outer Qi 8 interlock within the Zhen Group (Thunder ☳ · Chấn Cung) separates authentic lineage mastery from textbook guesswork.

2. Dual Classification Mechanics: Jing Fang 8-Palace Lineage vs. San Yuan Upper-Trigram Gua Qi 8 Ring

Stop right here. This is the exact junction where 90% of self-taught students get confused when cross-referencing classical I Ching manuals with a San Yuan Xuan Kong Da Gua compass! Why do some texts list the 8 hexagrams of the Zhen Group (Thunder ☳ · Chấn Cung) as #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #46 Địa Phong Thăng (䷭), #48 Thủy Phong Tỉnh (䷯), #28 Trạch Phong Đại Quá (䷛), #17 Trạch Lôi Tùy (䷐), whereas the outer Gua Qi table of a San Yuan Luo Pan lists the 8 hexagrams of Gua Qi 8 (Zhen ☳) as #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), #62 Lôi Sơn Tiểu Quá (䷽)? Both lists are 100% authentic. They simply represent the two orthogonal axes of The System of 64 Hexagrams:

AXIS 1 · ANCESTRAL SOUL

Jing Fang's Eight-Palace Transformation (Bát Cung Kinh Phòng 京房八宮)

Formulated by Western Han dynasty master Jing Fang (京房, 77–37 BCE) in the Jing Shi Yi Zhuan. Starting from the doubled pure hexagram #51 Chấn Vi Lôi (䷲), lines transform sequentially from bottom to top: 1st Yao (1st Gen), 2nd Yao (2nd Gen), 3rd Yao (3rd Gen), 4th Yao (4th Gen), 5th Yao (5th Gen), back to 4th Yao (Wandering Soul / Du Hồn), and finally restoring the lower 3 lines to the root trigram (Returning Soul / Quy Hồn). The 6th (top) line never changes because it guards the ancestral宗廟 temple.

AXIS 2 · COMPASS GUA QI

San Yuan Upper-Trigram Gua Qi Ring (Ngoại Quái Quái Khí 卦氣環)

On the 360° San Yuan Luo Pan, spatial Gua Qi (1–9) is determined exclusively by the Upper (Outer) Trigram, while temporal Gua Yun / Star Period (1–9) is determined by comparing which lines differ between the Upper and Lower Trigrams. Therefore, all 8 hexagrams that share Zhen ☳ as their Upper Trigram share Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)) and span all 8 Star Periods (1, 2, 3, 4, 6, 7, 8, 9).

Look at the mathematical bridge between Axis 1 and Axis 2. In Jing Fang's 8-step transformation of the Zhen Group (Thunder ☳ · Chấn Cung):

Steps 0, 1, 2, and 3 (Pure Root #51, 1st Gen #16, 2nd Gen #40, and 3rd Gen #32): Because only the Lower (Inner) Trigram lines change during the first three generations, their Upper (Outer) Trigram remains Zhen ☳! Consequently, these first four hexagrams carry Gua Qi 8 and belong to both the Jing Fang Zhen Palace and the Upper-Zhen Compass Ring! Specifically, Step 0 (#51 Chấn Vi Lôi) is the Period 1 Upper-Cycle Parent, Step 1 (#16 Lôi Địa Dự) is the Period 2 Jiangdong Hexagram, Step 2 (#40 Lôi Thủy Giải) is the Period 6 North-South Opposite Hexagram, and Step 3 (#32 Lôi Phong Hằng) is the Period 9 Lower-Cycle Parent!
Steps 4, 5, 6, and 7 (4th Gen #46, 5th Gen #48, Wandering Soul #28, and Returning Soul #17): Once the Jing Fang transformation climbs into the 4th and 5th lines, the Upper Trigram changes from Zhen ☳ into four other trigrams! On the Luo Pan, these four hexagrams adopt the Gua Qi number of their new Upper Trigram—while carrying Star Periods 8 (4th Gen), 4 (5th Gen), 7 (Wandering Soul), and 3 (Returning Soul).
The 4 Cross-Palace Complements (#34, #54, #55, and #62): Conversely, four hexagrams born as the 4th Gen, 5th Gen, Wandering Soul, and Returning Soul of other Jing Fang palaces acquire Zhen ☳ as their Upper Trigram—supplying Star Periods 4, 3, 8, and 7 inside the Gua Qi 8 compass family!

Figure 1: The 8 Jing Fang Palace Hexagrams (Bát Cung Kinh Phòng) of the Zhen Group (Thunder ☳ · Chấn Cung) showing line-transformation steps, Gua Qi numbers, Star Periods, and 24-Mountain arcs.

By mastering both sets—all 8 Jing Fang Palace hexagrams and their 4 Upper-Zhen Compass Ring complements (12 hexagrams in total, with 4 shared at the core)—you command the entire theoretical and practical spectrum of the Zhen Group (Thunder ☳ · Chấn Cung).

3. Master Reference Matrix: Complete 8 Jing Fang Palace Hexagrams & 8 Upper-Zhen Compass Hexagrams

Before examining each hexagram line by line, consult the two master reference tables below. Table 1 synthesizes the 8 Jing Fang Palace Hexagrams of the Zhen Group (Thunder ☳ · Chấn Cung), while Table 2 synthesizes the 8 San Yuan Upper-Zhen Compass Ring Hexagrams that share Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)).

Table 1: The 8 Jing Fang Palace Hexagrams (Bát Cung Kinh Phòng) of the Zhen Group (Thunder ☳ · Chấn Cung)
King Wen # & Hexagram	Jing Fang Step	Upper / Lower	Da Gua Qi & Element	Gua Yun (Star Period)	360° Compass Arc & Red Yao	Period 9 (2024–2043) Role
#51 Chấn Vi Lôi Zhen (The Arousing Thunder) · 震為雷 ䷲	0. Pure Root (Bát Thuần)	Zhen ☳ / Zhen ☳	Gua Qi 8 Yin Wood (3-8 Wood)	Period 1 Greedy Wolf (Tan Lang)	Thìn (135.000°–140.625°) Red: Yao 1 (135.000°–135.938°), Yao 4 (137.813°–138.750°)	★ Supreme Period 9 Indirect Spirit (Period 1 + Period 9 = 10; Gua Qi 8 Wood)
#16 Lôi Địa Dự Yu (Enthusiasm / Preparation) · 雷地豫 ䷏	1. 1st Gen (Nhất Thế)	Zhen ☳ / Kun ☷	Gua Qi 8 Yin Wood (3-8 Wood)	Period 2 Giant Gate (Ju Men)	Thìn – Tỵ (140.625°–146.250°) Red: Yao 2 (141.563°–142.500°), Yao 4 (143.438°–144.375°)	Upper Cycle Indirect Spirit (Internal Sum of Ten: Gua Qi 8 + Period 2 = 10)
#40 Lôi Thủy Giải Jie (Deliverance / Release) · 雷水解 ䷧	2. 2nd Gen (Nhị Thế)	Zhen ☳ / Kan ☵	Gua Qi 8 Yin Wood (3-8 Wood)	Period 6 Military Arts (Wu Qu)	Ngọ (174.375°–180.000°) Red: Yao 2 (175.313°–176.250°), Yao 4 (177.188°–178.125°), Yao 5 (178.125°–179.063°)	Lower Cycle Direct Spirit Group (Gua Qi 8 Wood · Period 6)
#32 Lôi Phong Hằng Heng (Duration / Perseverance) · 雷風恒 ䷟	3. 3rd Gen (Tam Thế)	Zhen ☳ / Xun ☴	Gua Qi 8 Yin Wood (3-8 Wood)	Period 9 Right Assistant (You Bi)	Bính – Ngọ (163.125°–168.750°) Red: Yao 2 (164.063°–165.000°), Yao 3 (165.000°–165.938°), Yao 5 (166.875°–167.813°)	★ TIMELY PERIOD 9 PARENT DIRECT SPIRIT (Period 9 + Gua Qi 8 Wood)
#46 Địa Phong Thăng Sheng (Pushing Upward / Ascending) · 地風升 ䷭	4. 4th Gen (Tứ Thế)	Kun ☷ / Xun ☴	Gua Qi 1 Yang Water (1-6 Water)	Period 8 Left Assistant (Zuo Fu)	Hợi (331.875°–337.500°) Red: Yao 1 (331.875°–332.813°), Yao 2 (332.813°–333.750°), Yao 4 (334.688°–335.625°), Yao 5 (335.625°–336.563°)	Lower Cycle Direct Spirit Group · Gua Qi 1 Sum-of-Ten with Qian 9 (1+9=10)
#48 Thủy Phong Tỉnh Jing (The Well) · 水風井 ䷯	5. 5th Gen (Ngũ Thế)	Kan ☵ / Xun ☴	Gua Qi 7 Yang Fire (2-7 Fire)	Period 4 Literary Arts (Wen Qu)	Giáp – Mão (84.375°–90.000°) Red: Yao 4 (87.188°–88.125°), Yao 5 (88.125°–89.063°), Yao 6 (89.063°–90.000°)	Upper Cycle Indirect Spirit (5th Gen of Zhen · Gua Qi 7 Fire · Period 4)
#28 Trạch Phong Đại Quá Da Guo (Preponderance of the Great) · 澤風大過 ䷛	6. Wandering Soul (Du Hồn)	Dui ☱ / Xun ☴	Gua Qi 4 Yin Metal (4-9 Metal)	Period 7 Broken Army (Po Jun)	Mùi – Khôn (202.500°–208.125°) Red: Yao 2 (203.438°–204.375°), Yao 4 (205.313°–206.250°)	Upper-Dui Gua Qi 4 Metal · Wandering Soul of Zhen (Lower Cycle Period 7)
#17 Trạch Lôi Tùy Sui (Following) · 澤雷隨 ䷐	7. Returning Soul (Quy Hồn)	Dui ☱ / Zhen ☳	Gua Qi 4 Yin Metal (4-9 Metal)	Period 3 Rank / Lu Cun	Dậu – Tân (277.500°–283.125°) Red: Yao 1 (277.500°–278.438°), Yao 4 (280.313°–281.250°), Yao 5 (281.250°–282.188°)	Upper-Dui Gua Qi 4 Metal · Returning Soul of Zhen (Period 3 Indirect Spirit)

Table 2: The 8 San Yuan Compass Ring Hexagrams Sharing Upper Trigram Zhen ☳ (All Carrying Gua Qi 8 — Yin Wood (He Tu 3–8 Companion Wood))
King Wen # & Hexagram	Upper / Lower	Outer Gua Qi	Star Period (Gua Yun)	Jing Fang Overlap	360° Fu Xi Compass Arc	Sum-of-Ten (He Shi) Targets
#51 Chấn Vi Lôi (震為雷 ䷲)	Zhen ☳ / Zhen ☳	Gua Qi 8 (Yin Wood)	Period 1 (Greedy Wolf (Tan Lang))	Yes (Steps 0–3)	Thìn (135.000°–140.625°)	Gua Qi 2 (He Shi) · Period 9 (He Shi)
#16 Lôi Địa Dự (雷地豫 ䷏)	Zhen ☳ / Kun ☷	Gua Qi 8 (Yin Wood)	Period 2 (Giant Gate (Ju Men))	Yes (Steps 0–3)	Thìn – Tỵ (140.625°–146.250°)	Gua Qi 2 (He Shi) · Period 8 (He Shi)
#40 Lôi Thủy Giải (雷水解 ䷧)	Zhen ☳ / Kan ☵	Gua Qi 8 (Yin Wood)	Period 6 (Military Arts (Wu Qu))	Yes (Steps 0–3)	Ngọ (174.375°–180.000°)	Gua Qi 2 (He Shi) · Period 4 (He Shi)
#32 Lôi Phong Hằng (雷風恒 ䷟)	Zhen ☳ / Xun ☴	Gua Qi 8 (Yin Wood)	Period 9 (Right Assistant (You Bi))	Yes (Steps 0–3)	Bính – Ngọ (163.125°–168.750°)	Gua Qi 2 (He Shi) · Period 1 (He Shi)
#34 Lôi Thiên Đại Tráng (雷天大壯 ䷡)	Zhen ☳ / Qian ☰	Gua Qi 8 (Yin Wood)	Period 8 (Left Assistant (Zuo Fu))	Cross-Palace (Steps 4–7)	Tỵ – Bính (157.500°–163.125°)	Gua Qi 2 (He Shi) · Period 2 (He Shi)
#54 Lôi Trạch Quy Muội (雷澤歸妹 ䷵)	Zhen ☳ / Dui ☱	Gua Qi 8 (Yin Wood)	Period 3 (Rank / Lu Cun)	Cross-Palace (Steps 4–7)	Tỵ (151.875°–157.500°)	Gua Qi 2 (He Shi) · Period 7 (He Shi)
#55 Lôi Hỏa Phong (雷火豐 ䷶)	Zhen ☳ / Li ☲	Gua Qi 8 (Yin Wood)	Period 4 (Literary Arts (Wen Qu))	Cross-Palace (Steps 4–7)	Thìn – Tỵ (146.250°–151.875°)	Gua Qi 2 (He Shi) · Period 6 (He Shi)
#62 Lôi Sơn Tiểu Quá (雷山小過 ䷽)	Zhen ☳ / Gen ☶	Gua Qi 8 (Yin Wood)	Period 7 (Broken Army (Po Jun))	Cross-Palace (Steps 4–7)	Bính – Ngọ (168.750°–174.375°)	Gua Qi 2 (He Shi) · Period 3 (He Shi)

Figure 2: Comparison of the 8 Upper-Zhen Compass Ring Hexagrams (all carrying Gua Qi 8) and their overlap with the Jing Fang Zhen Palace.

Notice the mathematical elegance in Table 2: within the 8 hexagrams sharing Upper Trigram Zhen ☳, every single Star Period from 1 to 9 (excluding the central 5) appears exactly once (1, 2, 3, 4, 6, 7, 8, 9). Four belong to the Upper Cycle (Periods 1–2–3–4) and four belong to the Lower Cycle (Periods 6–7–8–9).

4. Deep-Dive Monograph Pt. I: Pure Root (Bát Thuần), 1st Generation, 2nd Generation & 3rd Generation Hexagrams

Let us now dissect the first four hexagrams of the Zhen Group (Thunder ☳ · Chấn Cung): #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), and #32 Lôi Phong Hằng (䷟). Because all four retain Zhen ☳ as their Upper (Outer) Trigram, all four carry Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)) and progress from Pure Root (Period 1) through 1st Gen (Period 2) and 2nd Gen (Period 6) to culmination at the 3rd-Generation Parent Hexagram (Period 9)!

King Wen #51 · Zhèn Wéi Léi · Jing Fang Step 0

#51. Chấn Vi Lôi — Zhen (The Arousing Thunder) (震為雷 ䷲) · Gua Qi 8 & Period 1

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Zhen ☳. Jing Fang Step 0: Pure Palace Root (Bát Thuần Quái · 八純卦). Because its Upper (Outer) Trigram is Zhen ☳ and its Jing Fang transformation remains within the lower three lines, #51 Chấn Vi Lôi (震為雷 ䷲) belongs simultaneously to the Jing Fang Zhen Palace and the San Yuan Upper-Zhen Gua Qi 8 Compass Ring. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #51 Chấn Vi Lôi carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 1 · Greedy Wolf (Tan Lang) (Upper Cycle Parent (Periods 1–4)), forming temporal Sum-of-Ten with Star Period 9 (1 + 9 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Thìn (135.000°–140.625°) within the Thìn / Tốn (SE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 1 (135.000°–135.938°), Yao 4 (137.813°–138.750°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 135.000° ±0.75° (Thìn–Tốn 45° Corner Void), 140.625° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): ★ Supreme Period 9 Indirect Spirit (Period 1 + Period 9 = 10; Gua Qi 8 Wood). Pure Thunder Eldest Son hexagram. Forms Period 1+9=10 Sum-of-Ten Indirect Spirit for rapid entrepreneurial launch, gates, and water mouths; pairs with Xun Gua Qi 2 (8+2=10). When activating #51 Chấn Vi Lôi via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

King Wen #16 · Léi Dì Yù · Jing Fang Step 1

#16. Lôi Địa Dự — Yu (Enthusiasm / Preparation) (雷地豫 ䷏) · Gua Qi 8 & Period 2

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Kun ☷. Jing Fang Step 1: 1st Generation (Nhất Thế Quái · 一世卦). Because its Upper (Outer) Trigram is Zhen ☳ and its Jing Fang transformation remains within the lower three lines, #16 Lôi Địa Dự (雷地豫 ䷏) belongs simultaneously to the Jing Fang Zhen Palace and the San Yuan Upper-Zhen Gua Qi 8 Compass Ring. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #16 Lôi Địa Dự carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 2 · Giant Gate (Ju Men) (Upper Cycle Jiangdong (1st Yao Change · 1st Gen of Zhen)), forming temporal Sum-of-Ten with Star Period 8 (2 + 8 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Thìn – Tỵ (140.625°–146.250°) within the Tốn (SE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (141.563°–142.500°), Yao 4 (143.438°–144.375°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 140.625° ±0.45°, 146.250° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Upper Cycle Indirect Spirit (Internal Sum of Ten: Gua Qi 8 + Period 2 = 10). Built-in Sum-of-Ten hexagram (Gua Qi 8 + Period 2 = 10)! Thunder bursting joyfully from Earth on Yao 4 ('Source of enthusiasm, great achievements') empowers Main Gates and auditoriums. When activating #16 Lôi Địa Dự via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

King Wen #40 · Léi Shuǐ Jiě · Jing Fang Step 2

#40. Lôi Thủy Giải — Jie (Deliverance / Release) (雷水解 ䷧) · Gua Qi 8 & Period 6

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Kan ☵. Jing Fang Step 2: 2nd Generation (Nhị Thế Quái · 二世卦). Because its Upper (Outer) Trigram is Zhen ☳ and its Jing Fang transformation remains within the lower three lines, #40 Lôi Thủy Giải (雷水解 ䷧) belongs simultaneously to the Jing Fang Zhen Palace and the San Yuan Upper-Zhen Gua Qi 8 Compass Ring. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #40 Lôi Thủy Giải carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 6 · Military Arts (Wu Qu) (Lower Cycle North-South Opposite (2nd Gen of Zhen)), forming temporal Sum-of-Ten with Star Period 4 (6 + 4 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Ngọ (174.375°–180.000°) within the Ngọ (Due S) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (175.313°–176.250°), Yao 4 (177.188°–178.125°), Yao 5 (178.125°–179.063°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 174.375° ±0.45°, 180.000° ±0.75° (Due South Cardinal Void), where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Lower Cycle Direct Spirit Group (Gua Qi 8 Wood · Period 6). Spring thunder and rain untie knots of crisis and debt. Tapped on Yao 2 ('captures three foxes in the field, receives yellow arrows') for Sitting Mountain or Stove relief. When activating #40 Lôi Thủy Giải via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

King Wen #32 · Léi Fēng Héng · Jing Fang Step 3

#32. Lôi Phong Hằng — Heng (Duration / Perseverance) (雷風恒 ䷟) · Gua Qi 8 & Period 9

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Xun ☴. Jing Fang Step 3: 3rd Generation (Tam Thế Quái · 三世卦). Because its Upper (Outer) Trigram is Zhen ☳ and its Jing Fang transformation remains within the lower three lines, #32 Lôi Phong Hằng (雷風恒 ䷟) belongs simultaneously to the Jing Fang Zhen Palace and the San Yuan Upper-Zhen Gua Qi 8 Compass Ring. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #32 Lôi Phong Hằng carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 9 · Right Assistant (You Bi) (Lower Cycle Parent (All 3 Yao Opposite · 3rd Gen of Zhen)), forming temporal Sum-of-Ten with Star Period 1 (9 + 1 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Bính – Ngọ (163.125°–168.750°) within the Bính (SSE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (164.063°–165.000°), Yao 3 (165.000°–165.938°), Yao 5 (166.875°–167.813°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 163.125° ±0.45°, 168.750° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): ★ TIMELY PERIOD 9 PARENT DIRECT SPIRIT (Period 9 + Gua Qi 8 Wood). Eldest Son (Zhen) above and Eldest Daughter (Xun) below in enduring marital and dynastic longevity! One of the 8 Ruling Period-9 Parent Hexagrams—supreme for Sitting Mountain and Master Bed. When activating #32 Lôi Phong Hằng via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

5. Deep-Dive Monograph Pt. II: 4th Generation, 5th Generation, Wandering Soul (Du Hồn) & Returning Soul (Quy Hồn)

Once the 3rd Generation (#32 Lôi Phong Hằng) completes the transformation of the Lower Trigram, Jing Fang's line progression ascends into the Upper (Outer) Trigram across the 4th Generation (#46 Địa Phong Thăng), 5th Generation (#48 Thủy Phong Tỉnh), Wandering Soul (#28 Trạch Phong Đại Quá), and Returning Soul (#17 Trạch Lôi Tùy). Watch how the Outer Trigram shifts across the palaces while the inner ancestral pulse of the Zhen Group (Thunder ☳ · Chấn Cung) drives their destiny:

King Wen #46 · Dì Fēng Shēng · Jing Fang Step 4

#46. Địa Phong Thăng — Sheng (Pushing Upward / Ascending) (地風升 ䷭) · Gua Qi 1 & Period 8

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Kun ☷ over Lower (Inner) Trigram Xun ☴. Jing Fang Step 4: 4th Generation (Tứ Thế Quái · 四世卦). In the Jing Fang 8-Palace sequence, the transformation has ascended into the Upper Trigram (shifting the Outer Trigram to Kun ☷), so on the San Yuan Luo Pan its spatial Gua Qi becomes Gua Qi 1 (Yang Water (1-6 Water)) while its ancestral soul remains rooted in the Zhen Palace. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #46 Địa Phong Thăng carries Gua Qi 1 (Yang Water (1-6 Water)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 9 (1 + 9 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 6 (|1 − 6| = 5). On the inner Star Period ring, it carries Period 8 · Left Assistant (Zuo Fu) (Lower Cycle Jiangdong Opposite (4th Gen of Zhen)), forming temporal Sum-of-Ten with Star Period 2 (8 + 2 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Hợi (331.875°–337.500°) within the Hợi (NNW) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 1 (331.875°–332.813°), Yao 2 (332.813°–333.750°), Yao 4 (334.688°–335.625°), Yao 5 (335.625°–336.563°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 331.875° ±0.45°, 337.500° ±0.75° (Hợi–Nhâm Palace Border), where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Lower Cycle Direct Spirit Group · Gua Qi 1 Sum-of-Ten with Qian 9 (1+9=10). Living timber growing steadily out of fertile earth ('ascending the great stairs'). Exceptional for steady career promotion, civil service, and northwest Sitting Mountain. When activating #46 Địa Phong Thăng via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 1 (Pure One Qi), Gua Qi 9 (Sum of Ten), or Gua Qi 6 (He Tu Same-Element Completion).

King Wen #48 · Shuǐ Fēng Jǐng · Jing Fang Step 5

#48. Thủy Phong Tỉnh — Jing (The Well) (水風井 ䷯) · Gua Qi 7 & Period 4

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Kan ☵ over Lower (Inner) Trigram Xun ☴. Jing Fang Step 5: 5th Generation (Ngũ Thế Quái · 五世卦). In the Jing Fang 8-Palace sequence, the transformation has ascended into the Upper Trigram (shifting the Outer Trigram to Kan ☵), so on the San Yuan Luo Pan its spatial Gua Qi becomes Gua Qi 7 (Yang Fire (2-7 Fire)) while its ancestral soul remains rooted in the Zhen Palace. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #48 Thủy Phong Tỉnh carries Gua Qi 7 (Yang Fire (2-7 Fire)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 3 (7 + 3 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 2 (|7 − 2| = 5). On the inner Star Period ring, it carries Period 4 · Literary Arts (Wen Qu) (Upper Cycle North-South (5th Gen of Zhen)), forming temporal Sum-of-Ten with Star Period 6 (4 + 6 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Giáp – Mão (84.375°–90.000°) within the Mão (Due E) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 4 (87.188°–88.125°), Yao 5 (88.125°–89.063°), Yao 6 (89.063°–90.000°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 84.375° ±0.45°, 90.000° ±0.75° (Due East Cardinal Void), where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Upper Cycle Indirect Spirit (5th Gen of Zhen · Gua Qi 7 Fire · Period 4). Inexhaustible crystal spring ('The Well is lined with stone; cold crystal spring water'). On Yao 5, it is a premier eastern Water Mouth or courtyard fountain sector. When activating #48 Thủy Phong Tỉnh via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 7 (Pure One Qi), Gua Qi 3 (Sum of Ten), or Gua Qi 2 (He Tu Same-Element Completion).

King Wen #28 · Zé Fēng Dà Guò · Jing Fang Step 6

#28. Trạch Phong Đại Quá — Da Guo (Preponderance of the Great) (澤風大過 ䷛) · Gua Qi 4 & Period 7

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Dui ☱ over Lower (Inner) Trigram Xun ☴. Jing Fang Step 6: Wandering Soul (Du Hồn Quái · 遊魂卦). In the Jing Fang 8-Palace sequence, the transformation has ascended into the Upper Trigram (shifting the Outer Trigram to Dui ☱), so on the San Yuan Luo Pan its spatial Gua Qi becomes Gua Qi 4 (Yin Metal (4-9 Metal)) while its ancestral soul remains rooted in the Zhen Palace. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #28 Trạch Phong Đại Quá carries Gua Qi 4 (Yin Metal (4-9 Metal)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 6 (4 + 6 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 9 (|4 − 9| = 5). On the inner Star Period ring, it carries Period 7 · Broken Army (Po Jun) (Lower Cycle Jiangxi Opposite (Wandering Soul of Zhen)), forming temporal Sum-of-Ten with Star Period 3 (7 + 3 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Mùi – Khôn (202.500°–208.125°) within the Khôn (SW) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (203.438°–204.375°), Yao 4 (205.313°–206.250°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 202.500° ±0.75° (Mùi–Khôn Palace Border), 208.125° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Upper-Dui Gua Qi 4 Metal · Wandering Soul of Zhen (Lower Cycle Period 7). Must be anchored strictly on Yao 2 ('withered poplar sprouts shoots') or Yao 4 ('ridgepole braced') to avoid structural overextension. When activating #28 Trạch Phong Đại Quá via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 4 (Pure One Qi), Gua Qi 6 (Sum of Ten), or Gua Qi 9 (He Tu Same-Element Completion).

King Wen #17 · Zé Léi Suí · Jing Fang Step 7

#17. Trạch Lôi Tùy — Sui (Following) (澤雷隨 ䷐) · Gua Qi 4 & Period 3

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Dui ☱ over Lower (Inner) Trigram Zhen ☳. Jing Fang Step 7: Returning Soul (Quy Hồn Quái · 歸魂卦). In the Jing Fang 8-Palace sequence, the transformation has ascended into the Upper Trigram (shifting the Outer Trigram to Dui ☱), so on the San Yuan Luo Pan its spatial Gua Qi becomes Gua Qi 4 (Yin Metal (4-9 Metal)) while its ancestral soul remains rooted in the Zhen Palace. Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #17 Trạch Lôi Tùy carries Gua Qi 4 (Yin Metal (4-9 Metal)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 6 (4 + 6 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 9 (|4 − 9| = 5). On the inner Star Period ring, it carries Period 3 · Rank / Lu Cun (Upper Cycle Jiangxi (Returning Soul of Zhen)), forming temporal Sum-of-Ten with Star Period 7 (3 + 7 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Dậu – Tân (277.500°–283.125°) within the Dậu / Tân (W) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 1 (277.500°–278.438°), Yao 4 (280.313°–281.250°), Yao 5 (281.250°–282.188°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 277.500° ±0.75° (Dậu–Tân Palace Border), 283.125° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Upper-Dui Gua Qi 4 Metal · Returning Soul of Zhen (Period 3 Indirect Spirit). Eldest Son (Zhen) bows beneath Youngest Daughter (Dui). Excellent for commercial storefronts, hospitality gates, and customer flow when paired with Gen Gua Qi 6 (4+6=10). When activating #17 Trạch Lôi Tùy via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 4 (Pure One Qi), Gua Qi 6 (Sum of Ten), or Gua Qi 9 (He Tu Same-Element Completion).

6. Upper-Zhen Compass Ring Equivalents: The 4 Cross-Palace Hexagrams Completing the Gua Qi 8 Family

When you stand at the center of a building holding a San Yuan Xuan Kong Da Gua Luo Pan and look for sectors carrying Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood))—whether to build a Pure One Hexagram (Yi Gua Chun Qing) formation or to lock into Sum-of-Ten with Xun Group ☴ (Gua Qi 2 Fire · 8 + 2 = 10)—you must also command the four hexagrams whose Upper Trigram is Zhen ☳ even though their Jing Fang root lies in another palace: #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), and #62 Lôi Sơn Tiểu Quá (䷽).

King Wen #34 · Léi Tiān Dà Zhuàng · Upper-Zhen Compass Ring Member · Jiangdong Opposite (Left Assistant · Zuo Fu) — 2nd & 3rd Yao differ from Upper Trigram (1st changed from Period 9)

#34. Lôi Thiên Đại Tráng — Da Zhuang (The Power of the Great) (雷天大壯 ䷡) · Gua Qi 8 & Period 8

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Qian ☰. Upper-Zhen Compass Ring Member · Jiangdong Opposite (Left Assistant · Zuo Fu) — 2nd & 3rd Yao differ from Upper Trigram (1st changed from Period 9). While its Jing Fang ancestral root belongs to another palace's 4th/5th/Soul step, its Outer (Upper) Trigram is Zhen ☳—meaning on the 360° San Yuan Luo Pan it carries pure Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)) and completes the 8-hexagram Upper-Zhen ring! Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #34 Lôi Thiên Đại Tráng carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 8 · Left Assistant (Zuo Fu) (Lower Cycle Jiangdong Opposite (4th Gen of Kun · Upper-Zhen Ring)), forming temporal Sum-of-Ten with Star Period 2 (8 + 2 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Tỵ – Bính (157.500°–163.125°) within the Bính (SSE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (158.438°–159.375°), Yao 4 (160.313°–161.250°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 157.500° ±0.75° (Tỵ–Bính Palace Border), 163.125° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): ★ Double-8 Powerhouse (Gua Qi 8 Wood + Star Period 8 Direct Spirit Group). Four Yang lines surging beneath Thunder in the sky! Forms Double Sum-of-Ten (8+2=10 in both Gua Qi and Period) with Xun #9 Xiao Chu (Gua Qi 2, Period 2). When activating #34 Lôi Thiên Đại Tráng via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

King Wen #54 · Léi Zé Guī Mèi · Upper-Zhen Compass Ring Member · Jiangxi Hexagram (Rank · Lu Cun) — Only 2nd (middle) Yao differs from Upper Trigram

#54. Lôi Trạch Quy Muội — Gui Mei (The Marrying Maiden) (雷澤歸妹 ䷵) · Gua Qi 8 & Period 3

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Dui ☱. Upper-Zhen Compass Ring Member · Jiangxi Hexagram (Rank · Lu Cun) — Only 2nd (middle) Yao differs from Upper Trigram. While its Jing Fang ancestral root belongs to another palace's 4th/5th/Soul step, its Outer (Upper) Trigram is Zhen ☳—meaning on the 360° San Yuan Luo Pan it carries pure Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)) and completes the 8-hexagram Upper-Zhen ring! Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #54 Lôi Trạch Quy Muội carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 3 · Rank / Lu Cun (Upper Cycle Jiangxi (Returning Soul of Dui)), forming temporal Sum-of-Ten with Star Period 7 (3 + 7 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Tỵ (151.875°–157.500°) within the Tỵ (SSE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (152.813°–153.750°), Yao 5 (155.625°–156.563°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 151.875° ±0.45°, 157.500° ±0.75° (Tỵ–Bính Palace Border), where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Upper Cycle Indirect Spirit (Returning Soul of Dui · Gua Qi 8 Wood · Period 3). Returning Soul of Dui Palace. Must only be used on Yao 5 ('Emperor Yi gives his daughter in marriage') for secondary water features paired with Xun Gua Qi 2 (8+2=10). When activating #54 Lôi Trạch Quy Muội via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

King Wen #55 · Léi Huǒ Fēng · Upper-Zhen Compass Ring Member · North-South Eight Spirits (Literary · Wen Qu) — Only 3rd (top) Yao differs from Upper Trigram

#55. Lôi Hỏa Phong — Feng (Abundance / Fullness) (雷火豐 ䷶) · Gua Qi 8 & Period 4

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Li ☲. Upper-Zhen Compass Ring Member · North-South Eight Spirits (Literary · Wen Qu) — Only 3rd (top) Yao differs from Upper Trigram. While its Jing Fang ancestral root belongs to another palace's 4th/5th/Soul step, its Outer (Upper) Trigram is Zhen ☳—meaning on the 360° San Yuan Luo Pan it carries pure Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)) and completes the 8-hexagram Upper-Zhen ring! Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #55 Lôi Hỏa Phong carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 4 · Literary Arts (Wen Qu) (Upper Cycle North-South (5th Gen of Kan · Upper-Zhen Ring)), forming temporal Sum-of-Ten with Star Period 6 (4 + 6 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Thìn – Tỵ (146.250°–151.875°) within the Tốn / Tỵ (SE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (147.188°–148.125°), Yao 4 (149.063°–150.000°), Yao 5 (150.000°–150.938°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 146.250° ±0.45°, 151.875° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Upper-Zhen Gua Qi 8 Wood · Period 4 Indirect Spirit (5th Gen of Kan). Zenith sun and rolling thunder ('Be not sad; be like the sun at midday'). On Yao 5 ('Brings章庆 brilliant blessing and praise'), Feng (#55) magnetizes commercial abundance at the Main Gate. When activating #55 Lôi Hỏa Phong via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

King Wen #62 · Léi Shān Xiǎo Guò · Upper-Zhen Compass Ring Member · Jiangxi Opposite (Broken Army · Po Jun) — 1st & 3rd Yao differ from Upper Trigram (2nd changed from Period 9)

#62. Lôi Sơn Tiểu Quá — Xiao Guo (Preponderance of the Small) (雷山小過 ䷽) · Gua Qi 8 & Period 7

1. Structural & Trigram Anatomy: Upper (Outer) Trigram Zhen ☳ over Lower (Inner) Trigram Gen ☶. Upper-Zhen Compass Ring Member · Jiangxi Opposite (Broken Army · Po Jun) — 1st & 3rd Yao differ from Upper Trigram (2nd changed from Period 9). While its Jing Fang ancestral root belongs to another palace's 4th/5th/Soul step, its Outer (Upper) Trigram is Zhen ☳—meaning on the 360° San Yuan Luo Pan it carries pure Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood)) and completes the 8-hexagram Upper-Zhen ring! Measure the angle twice. Never guess.

2. Two-Ring Numerical Code (Gua Qi & Gua Yun): On the outer San Yuan Gua Qi ring, #62 Lôi Sơn Tiểu Quá carries Gua Qi 8 (Yin Wood (3-8 Wood)), which achieves Sum-of-Ten (He Shi 合十) resonance with Gua Qi 2 (8 + 2 = 10) and He Tu Generative Difference-of-Five (He Sheng Cheng 合生成) with Gua Qi 3 (|8 − 3| = 5). On the inner Star Period ring, it carries Period 7 · Broken Army (Po Jun) (Lower Cycle Jiangxi Opposite (Wandering Soul of Dui)), forming temporal Sum-of-Ten with Star Period 3 (7 + 3 = 10).

3. 360° Fu Xi Compass Arc & 384-Yao Line Division: Occupies the 5.625° horizon sector at Bính – Ngọ (168.750°–174.375°) within the Bính / Ngọ (SSE) mountain sector. Its prime Auspicious Red Jewel Lines (Hồng Tâm Cát Hào) are Yao 2 (169.688°–170.625°), Yao 5 (172.500°–173.438°) (each spanning exactly 0.9375°). Practitioners must strictly avoid the Void Taboo Zones (Không Vong Tuyến) at 168.750° ±0.45°, 174.375° ±0.45°, where qi scatters into erratic turbulence.

4. Period 9 (2024–2043) Field Application (Sitting, Facing, Gate, Stove & Water): Lower Cycle Direct Spirit Group (Wandering Soul of Dui · Gua Qi 8 Wood · Period 7). Favors conservative precision and financial auditing when tapped on Yao 2; pairs with Xun Gua Qi 2 (8+2=10) and Period 3 (7+3=10). When activating #62 Lôi Sơn Tiểu Quá via Xuan Kong Da Gua Date Selection, select Year, Month, Day, and Hour pillars carrying Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Same-Element Completion).

7. 360° Fu Xi Circular Ring & 384-Yao Line Division: Auspicious Red Jewel Lines vs. Void Taboos (Không Vong)

Precision is the lifeblood of The Compass in Practice. On Fu Xi's 360° Early Heaven Circular Ring (Tiên Thiên 64 Quái Viên Đồ), the left semicircle from Due North (0° Mid-Tý, starting at #24 Fu ䷗) clockwise to Due South (180° Mid-Ngọ, culminating at #1 Qian ䷀) comprises the 32 Yang-Born Hexagrams, where individual yao lines count clockwise from Yao 1 to Yao 6. Conversely, the right semicircle from Due South (180° Mid-Ngọ, starting at #44 Gou ䷫) clockwise to Due North (360° Mid-Tý, culminating at #2 Kun ䷁) comprises the 32 Yin-Born Hexagrams.

Every hexagram occupies exactly 360° ÷ 64 = 5.625°. Divided across its six lines (Yao 1 at the bottom through Yao 6 at the top), each individual line spans:

1 Hexagram Arc = 5.625° | 1 Individual Yao Arc = 5.625° ÷ 6 = 0.9375° (56 minutes 15 seconds of arc)

Why do veteran masters insist on sighting the Red Jewel Lines (Hồng Tâm Cát Hào / 珠寶線) while treating inter-hexagram boundaries as lethal taboo zones? Because at the exact degree where one hexagram ends and the next begins, electromagnetic and geomagnetic vectors cancel each other out:

1. Eight-Trigram Palace Boundary Great Void (Đại Không Vong Tuyến 大空亡): Occurs at the 8 cardinal and intercardinal boundaries separating the 8 Trigram Palaces (0°, 45°, 90°, 135°, 180°, 225°, 270°, 315°) and the 24-Mountain seams within±0.75°. Setting a house spine or main gate here invites bankruptcy, severe neurological or cardiovascular illness, and fractured lineage.
2. Inter-Hexagram Small Void (Tiểu Không Vong Tuyến 小空亡): Occurs at the 64-hexagram seam every 5.625° (within ±0.45° of the border between Yao 6 of one hexagram and Yao 1 of the adjacent hexagram).
3. Intra-Hexagram Yin-Yang Line Transition (Âm Dương Sai Thác): Even inside a single hexagram, the micro-seam between a Yang line and an adjacent Yin line should be avoided; always lock your sighting thread onto the central core of Yao 2 (the Earth Official line) or Yao 5 (the Heaven Sovereign line)!

Figure 3: High-precision 384-Yao angular breakdown (`0.9375°` per line) of the Period-9 Crown Hexagram #32 Lôi Phong Hằng (雷風恒 ䷟), highlighting Red Jewel Lines versus Void Taboo boundaries.

Table 3: Complete 384-Yao Compass Degree Breakdown, Red Jewel Lines & Void Taboos for All 12 Hexagrams Associated with the Zhen Group (Thunder ☳ · Chấn Cung)
Hexagram	5.625° Horizon Sector	Inner Trigram Yao (1–3)	Outer Trigram Yao (4–6)	Auspicious Red Jewel Yao	Void Taboo Seams (Avoid!)
#51 Chấn Vi Lôi ䷲ Gua Qi 8 · Period 1	Thìn (135.000°–140.625°) 24-Mtn: Thìn / Tốn (SE)	Y1: 135.00°–135.94° Y2: 135.94°–136.88° Y3: 136.88°–137.81°	Y4: 137.81°–138.75° Y5: 138.75°–139.69° Y6: 139.69°–140.62°	Yao 1 (135.000°–135.938°), Yao 4 (137.813°–138.750°)	135.000° ±0.75° (Thìn–Tốn 45° Corner Void), 140.625° ±0.45°
#16 Lôi Địa Dự ䷏ Gua Qi 8 · Period 2	Thìn – Tỵ (140.625°–146.250°) 24-Mtn: Tốn (SE)	Y1: 140.62°–141.56° Y2: 141.56°–142.50° Y3: 142.50°–143.44°	Y4: 143.44°–144.38° Y5: 144.38°–145.31° Y6: 145.31°–146.25°	Yao 2 (141.563°–142.500°), Yao 4 (143.438°–144.375°)	140.625° ±0.45°, 146.250° ±0.45°
#40 Lôi Thủy Giải ䷧ Gua Qi 8 · Period 6	Ngọ (174.375°–180.000°) 24-Mtn: Ngọ (Due S)	Y1: 174.38°–175.31° Y2: 175.31°–176.25° Y3: 176.25°–177.19°	Y4: 177.19°–178.12° Y5: 178.12°–179.06° Y6: 179.06°–180.00°	Yao 2 (175.313°–176.250°), Yao 4 (177.188°–178.125°), Yao 5 (178.125°–179.063°)	174.375° ±0.45°, 180.000° ±0.75° (Due South Cardinal Void)
#32 Lôi Phong Hằng ䷟ Gua Qi 8 · Period 9	Bính – Ngọ (163.125°–168.750°) 24-Mtn: Bính (SSE)	Y1: 163.12°–164.06° Y2: 164.06°–165.00° Y3: 165.00°–165.94°	Y4: 165.94°–166.88° Y5: 166.88°–167.81° Y6: 167.81°–168.75°	Yao 2 (164.063°–165.000°), Yao 3 (165.000°–165.938°), Yao 5 (166.875°–167.813°)	163.125° ±0.45°, 168.750° ±0.45°
#46 Địa Phong Thăng ䷭ Gua Qi 1 · Period 8	Hợi (331.875°–337.500°) 24-Mtn: Hợi (NNW)	Y1: 331.88°–332.81° Y2: 332.81°–333.75° Y3: 333.75°–334.69°	Y4: 334.69°–335.62° Y5: 335.62°–336.56° Y6: 336.56°–337.50°	Yao 1 (331.875°–332.813°), Yao 2 (332.813°–333.750°), Yao 4 (334.688°–335.625°), Yao 5 (335.625°–336.563°)	331.875° ±0.45°, 337.500° ±0.75° (Hợi–Nhâm Palace Border)
#48 Thủy Phong Tỉnh ䷯ Gua Qi 7 · Period 4	Giáp – Mão (84.375°–90.000°) 24-Mtn: Mão (Due E)	Y1: 84.38°–85.31° Y2: 85.31°–86.25° Y3: 86.25°–87.19°	Y4: 87.19°–88.12° Y5: 88.12°–89.06° Y6: 89.06°–90.00°	Yao 4 (87.188°–88.125°), Yao 5 (88.125°–89.063°), Yao 6 (89.063°–90.000°)	84.375° ±0.45°, 90.000° ±0.75° (Due East Cardinal Void)
#28 Trạch Phong Đại Quá ䷛ Gua Qi 4 · Period 7	Mùi – Khôn (202.500°–208.125°) 24-Mtn: Khôn (SW)	Y1: 202.50°–203.44° Y2: 203.44°–204.38° Y3: 204.38°–205.31°	Y4: 205.31°–206.25° Y5: 206.25°–207.19° Y6: 207.19°–208.12°	Yao 2 (203.438°–204.375°), Yao 4 (205.313°–206.250°)	202.500° ±0.75° (Mùi–Khôn Palace Border), 208.125° ±0.45°
#17 Trạch Lôi Tùy ䷐ Gua Qi 4 · Period 3	Dậu – Tân (277.500°–283.125°) 24-Mtn: Dậu / Tân (W)	Y1: 277.50°–278.44° Y2: 278.44°–279.38° Y3: 279.38°–280.31°	Y4: 280.31°–281.25° Y5: 281.25°–282.19° Y6: 282.19°–283.12°	Yao 1 (277.500°–278.438°), Yao 4 (280.313°–281.250°), Yao 5 (281.250°–282.188°)	277.500° ±0.75° (Dậu–Tân Palace Border), 283.125° ±0.45°
#34 Lôi Thiên Đại Tráng ䷡ Gua Qi 8 · Period 8	Tỵ – Bính (157.500°–163.125°) 24-Mtn: Bính (SSE)	Y1: 157.50°–158.44° Y2: 158.44°–159.38° Y3: 159.38°–160.31°	Y4: 160.31°–161.25° Y5: 161.25°–162.19° Y6: 162.19°–163.12°	Yao 2 (158.438°–159.375°), Yao 4 (160.313°–161.250°)	157.500° ±0.75° (Tỵ–Bính Palace Border), 163.125° ±0.45°
#54 Lôi Trạch Quy Muội ䷵ Gua Qi 8 · Period 3	Tỵ (151.875°–157.500°) 24-Mtn: Tỵ (SSE)	Y1: 151.88°–152.81° Y2: 152.81°–153.75° Y3: 153.75°–154.69°	Y4: 154.69°–155.62° Y5: 155.62°–156.56° Y6: 156.56°–157.50°	Yao 2 (152.813°–153.750°), Yao 5 (155.625°–156.563°)	151.875° ±0.45°, 157.500° ±0.75° (Tỵ–Bính Palace Border)
#55 Lôi Hỏa Phong ䷶ Gua Qi 8 · Period 4	Thìn – Tỵ (146.250°–151.875°) 24-Mtn: Tốn / Tỵ (SE)	Y1: 146.25°–147.19° Y2: 147.19°–148.12° Y3: 148.12°–149.06°	Y4: 149.06°–150.00° Y5: 150.00°–150.94° Y6: 150.94°–151.88°	Yao 2 (147.188°–148.125°), Yao 4 (149.063°–150.000°), Yao 5 (150.000°–150.938°)	146.250° ±0.45°, 151.875° ±0.45°
#62 Lôi Sơn Tiểu Quá ䷽ Gua Qi 8 · Period 7	Bính – Ngọ (168.750°–174.375°) 24-Mtn: Bính / Ngọ (SSE)	Y1: 168.75°–169.69° Y2: 169.69°–170.62° Y3: 170.62°–171.56°	Y4: 171.56°–172.50° Y5: 172.50°–173.44° Y6: 173.44°–174.38°	Yao 2 (169.688°–170.625°), Yao 5 (172.500°–173.438°)	168.750° ±0.45°, 174.375° ±0.45°

8. Supreme Hexagram Pairing Laws: Pure One Hexagram, Sum of Ten & Generative Difference of Five

Selecting a single auspicious hexagram for the Sitting Mountain is only 25% of a Xuan Kong Da Gua audit. In Principles of Trigram Pairing, the four spatial pillars of a building—Incoming Dragon (Lai Long 來龍), Sitting Mountain (Tọa Sơn 坐山), Facing Direction (Hướng Thủ 向首), and Water Mouth / Main Gate (Thủy Khẩu / Đại Môn 水口大門)—must lock into mathematical resonance through four classical formulas:

LAW 1 · YI GUA CHUN QING

Pure One Hexagram (Nhất Quái Thuần Thanh 一卦純清)

All four positions share Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood))—selecting exclusively from the 8 Upper-Zhen hexagrams (#51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), #62 Lôi Sơn Tiểu Quá (䷽))—or all four positions share Star Period 9 (such as pairing #32 Lôi Phong Hằng with another Period-9 Parent Hexagram). Zero five-phase friction; pure imperial authority.

LAW 2 · HE SHI (SUM = 10)

Husband-Wife Sum of Ten (Tiên Hậu Thiên Hợp Thập 合十)

Pairs any Upper-Zhen hexagram carrying Gua Qi 8 with any hexagram from the Xun Group ☴ (Gua Qi 2 Fire · 8 + 2 = 10) (8 + 2 = 10), OR pairs #32 Lôi Phong Hằng (Period 9) with #51 Chấn Vi Lôi (Period 1) so their Star Periods sum to 9 + 1 = 10! Unlocks complete Yin-Yang communication across the floor plan.

LAW 3 · HE SHENG CHENG (DIFF = 5)

He Tu Generative Difference of Five (Hợp Sinh Thành 合生成)

Pairs any Upper-Zhen hexagram carrying Gua Qi 8 with any hexagram from the Li Group ☲ (Gua Qi 3 Wood · 8 – 3 = 5) (|8 − 3| = 5). Because both groups belong to the exact same He Tu Five Phase (Yin Wood (He Tu 3–8 Companion Wood)), Yang creation and Yin completion merge into one family.

LAW 4 · SAN BAN GUA

Three-Group Parent String (Tam Ban Phụ Mẫu 1-4-7 · 2-5-8 · 3-6-9)

Connects hexagrams along the Jiangdong (1–4–7), Jiangxi (2–5–8), or North-South (3–6–9) strings to circulate Qi across complex multi-wing estates where 180° opposition is blocked by urban topography.

Test your layout against these four laws. Whenever Sitting and Facing share a 180° axis on the Fu Xi Circular Ring, their hexagrams are exact 6-line Yin-Yang inversions of each other—meaning their Upper Trigrams are Early Heaven opposites whose Gua Qi numbers always add up to 10, while their relative line differences remain identical so their Star Period numbers are 100% identical (Pure One Period Qi)! The real art lies in positioning the Main Gate (Đại Môn) and Water Mouth (Thủy Khẩu) so that all four vectors belong to at most two resonant numbers.

9. Period 9 (2024–2043) Field Operations: Direct Spirit (Chính Thần) Mountain & Indirect Spirit (Linh Thần) Water

On February 4, 2024 (Li Chun of the Jia Chen year), the planet crossed the threshold into Lower Cycle Period 9 (2024–2043), governed by Later Heaven Nine Purple Li Fire (九紫離火). In Chính Thần and Linh Thần, the law of Mountain and Water placement in Xuan Kong Da Gua is absolute: “Put Direct Spirit on the Mountain; put Indirect Spirit in the Water” (Chính Thần thượng sơn, Linh Thần hạ thủy 正神上山，零神下水).

How does this law apply specifically to the Zhen Group (Thunder ☳ · Chấn Cung) between 2024 and 2043?

1. The Lower-Cycle Direct Spirit Group (Chính Thần Đương Vận — Star Periods 6, 7, 8, and above all Period 9): Within the Zhen Group (Thunder ☳ · Chấn Cung), the supreme Timely Direct Spirit is the 3rd-Generation Parent Hexagram #32 Lôi Phong Hằng (雷風恒 ䷟) at Bính – Ngọ (163.125°–168.750°) (carrying Star Period 9 and Gua Qi 8), supported by the Lower-Cycle cohorts #40 Lôi Thủy Giải (Period 6), #28 Trạch Phong Đại Quá (Period 7), and #46 Địa Phong Thăng (Period 8). Place high terrain, solid structural backing, the Sitting spine of the building, the CEO throne, and the Master Bed here. Never excavate a deep pool or open a wide low-lying drainage gate on #32 Lôi Phong Hằng without a secondary water lock, lest you commit “Direct Spirit Falling into Water” (Chính Thần hạ thủy).
2. The Upper-Cycle Indirect Spirit Group (Linh Thần Hợp Thập — Star Periods 1, 2, 3, 4): Because Period 1 + Period 9 = 10, the Pure Root Hexagram #51 Chấn Vi Lôi (震為雷 ䷲) at Thìn (135.000°–140.625°) (carrying Star Period 1 and Gua Qi 8) acts as the Supreme Sum-of-Ten Indirect Spirit! Supported by #16 Lôi Địa Dự (Period 2), #17 Trạch Lôi Tùy (Period 3), and #48 Thủy Phong Tỉnh (Period 4), these sectors thrive when activated by open Bright Hall (Minh Đường) plazas, road junctions, main entrance gates, swimming pools, and water mouths.

Figure 4: Period 9 (2024–2043) Mountain and Water operational diagram for the Zhen Group (Thunder ☳ · Chấn Cung), pairing Direct Spirit #32 Lôi Phong Hằng with Sum-of-Ten Indirect Spirit #51 Chấn Vi Lôi.

10. Architectural Layout & Three Essentials (Sitting, Facing, Main Gate, Stove, Bed & Water Mouth) + 2026–2027 Audit

How do we translate these compass degrees into concrete architectural drawings for a villa, corporate office, or urban apartment? In Practical Application, we stand at the geometric heart of the floor plan (the Taiji Center—or the center of the main living room/office suite for irregular layouts) and project rays to the five key functional hubs:

Sitting Mountain & Building Spine (Tọa Sơn): Lock the sitting degree onto Yao 2 or Yao 5 of #32 Lôi Phong Hằng (䷟) (Star Period 9 Direct Spirit) or #40 Lôi Thủy Giải (䷧) (Star Period 6).
Main Entrance Gate & Reception Door (Đại Môn / Nạp Khí Khẩu): Position or angle the main door leaf onto an auspicious Red Yao of #51 Chấn Vi Lôi (䷲) (Star Period 1 → 1 + 9 = 10 Indirect Spirit) or #17 Trạch Lôi Tùy (䷐) (Returning Soul wealth retention).
Kitchen Stove & Wealth Alchemy (Táo Vị): Set the stove in a clean sector where its Gua Qi Five Phase either produces or matches the Sitting Mountain's Gua Qi (for Zhen Group (Thunder ☳ · Chấn Cung) Gua Qi 8 Yin Wood (He Tu 3–8 Companion Wood), pair with Xun Group ☴ (Gua Qi 2 Fire · 8 + 2 = 10) or Li Group ☲ (Gua Qi 3 Wood · 8 – 3 = 5)), while aligning the stove switch/mouth toward a Red Jewel Yao. Strictly avoid placing a fiery stove on Northwest Càn degrees where Fire attacks Heaven's Gate.
Master Bed & Executive Command Desk (Chủ Sàng & Bàn Tổng Giám Đốc): Anchor the bedhead or executive chair in the Micro-Taiji sector of #32 Lôi Phong Hằng or #46 Địa Phong Thăng so the occupant absorbs Timely Lower-Cycle Direct Spirit support.
Water Mouth, Swimming Pool & Drainage Weir (Thủy Khẩu): Ensure incoming water or courtyard fountains sit on #51 Chấn Vi Lôi or #16 Lôi Địa Dự, and never allow outgoing drainage to cross a Void Seam.

Figure 5: Practical architectural alignment blueprint from the property's Taiji Center, linking #32 Lôi Phong Hằng (Sitting), #51 Chấn Vi Lôi (Main Gate), #40 Lôi Thủy Giải (Stove/Vault), and #17 Trạch Lôi Tùy (Water Mouth).

Table 4: Architectural Three-Essentials Rating Matrix for the Zhen Group (Thunder ☳ · Chấn Cung) in Period 9 (2024–2043)
Hexagram	Sitting Spine / Master Bed	Main Gate / Water Mouth	Gua Qi Pairing Formula	Kitchen Stove & Vault Protocol
#51 Chấn Vi Lôi (䷲) Qi 8 · Yun 1	★★☆☆☆ Better for Water/Gate	★★★★★ Supreme 1+9=10 Indirect Spirit	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#16 Lôi Địa Dự (䷏) Qi 8 · Yun 2	★★☆☆☆ Better for Water/Gate	★★★★☆ Strong Upper-Cycle Water	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#40 Lôi Thủy Giải (䷧) Qi 8 · Yun 6	★★★★☆ Strong Lower-Cycle Sitting	★★★☆☆ Secondary / Pair via Gua Qi	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#32 Lôi Phong Hằng (䷟) Qi 8 · Yun 9	★★★★★ Supreme Direct Spirit	★★★☆☆ Secondary / Pair via Gua Qi	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#46 Địa Phong Thăng (䷭) Qi 1 · Yun 8	★★★★☆ Strong Lower-Cycle Sitting	★★★☆☆ Secondary / Pair via Gua Qi	Pair with Gua Qi 9 (Sum of 10) or Gua Qi 1 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#48 Thủy Phong Tỉnh (䷯) Qi 7 · Yun 4	★★☆☆☆ Better for Water/Gate	★★★★☆ Strong Upper-Cycle Water	Pair with Gua Qi 3 (Sum of 10) or Gua Qi 7 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#28 Trạch Phong Đại Quá (䷛) Qi 4 · Yun 7	★★★★☆ Strong Lower-Cycle Sitting	★★★☆☆ Secondary / Pair via Gua Qi	Pair with Gua Qi 6 (Sum of 10) or Gua Qi 4 (Pure One)	Align stove knob to Red Yao; avoid NW Càn Fire Burning Heaven's Gate
#17 Trạch Lôi Tùy (䷐) Qi 4 · Yun 3	★★☆☆☆ Better for Water/Gate	★★★★☆ Strong Upper-Cycle Water	Pair with Gua Qi 6 (Sum of 10) or Gua Qi 4 (Pure One)	Align stove knob to Red Yao; avoid NW Càn Fire Burning Heaven's Gate
#34 Lôi Thiên Đại Tráng (䷡) Qi 8 · Yun 8	★★★★☆ Strong Lower-Cycle Sitting	★★★☆☆ Secondary / Pair via Gua Qi	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#54 Lôi Trạch Quy Muội (䷵) Qi 8 · Yun 3	★★☆☆☆ Better for Water/Gate	★★★★☆ Strong Upper-Cycle Water	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#55 Lôi Hỏa Phong (䷶) Qi 8 · Yun 4	★★☆☆☆ Better for Water/Gate	★★★★☆ Strong Upper-Cycle Water	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao
#62 Lôi Sơn Tiểu Quá (䷽) Qi 8 · Yun 7	★★★★☆ Strong Lower-Cycle Sitting	★★★☆☆ Secondary / Pair via Gua Qi	Pair with Gua Qi 2 (Sum of 10) or Gua Qi 8 (Pure One)	Favorable Wood/Fire/Water-bridged hearth on Red Yao

🔥 Urgent Annual Timing Advisory: 2026 (Bing Wu) & 2027 (Ding Wei) Fire Peak

2026 (Bính Ngọ — Heavenly River Water / Double Yang Fire Horse) and 2027 (Đinh Mùi — Heavenly River Water / Yin Fire Goat) represent the blazing solar zenith of early Period 9! During 2026, the Grand Duke (Thái Tuế) sits in Due South Ngọ (172.5°–187.5°, overlapping #40 Jie ䷧ and #44 Gou ䷫) while the Three Killings (Tam Sát)and歲破 Year Breaker occupy Due North Tý (352.5°–7.5°, overlapping #24 Fu ䷗, #2 Kun ䷁, and #23 Bo ䷖). In 2027, Thái Tuế shifts to Mùi (195°–210°, overlapping #12 Pi ䷋ and #28 Da Guo ䷛) while Year Breaker strikes Sửu (15°–30°, overlapping #27 Yi ䷚, #22 Bi ䷕, and #41 Sun ䷨). When groundbreaking or renovating any sector of the Zhen Group (Thunder ☳ · Chấn Cung) in 2026–2027, never excavate first in the Thái Tuế or Tam Sát mountain; instead, initiate construction in a Sum-of-Ten auspicious sector using a Three-Cycle Xuan Kong Da Gua Date Chart to harmonize the annual spirit.

11. Three-Cycle Xuan Kong Da Gua Date Selection (Ze Ri) & Real-World Field Case Studies

Spatial alignment is the hardware; time is the high-voltage current that brings the circuit to life. In classical San Yuan Xuan Kong Da Gua Date Selection (Huyền Không Đại Quái Trạch Nhật), each of the 60 Jiazi (Lục Thập Hoa Giáp) pillars of Year, Month, Day, and Hour maps to a specific hexagram carrying its own Gua Qi (1–9) and Star Period (1–9). When selecting a date to break ground, install a main gate, set a stove, or move into a property governed by the Zhen Group (Thunder ☳ · Chấn Cung) (Gua Qi 8 — Yin Wood (He Tu 3–8 Companion Wood)), apply three golden rules:

Rule 1 — Pure One Qi Date Chart (Nhất Quái Thuần Thanh Khóa): All four pillars (Year, Month, Day, Hour) carry Gua Qi 8, matching the Sitting Mountain's Gua Qi 8 so that 5 pillars (4 time pillars + 1 space pillar) vibrate on a single frequency.
Rule 2 — Sum-of-Ten Husband-Wife Date Chart (Tiên Hậu Thiên Hợp Thập Khóa): The four time pillars combine Gua Qi 8 and Gua Qi 2 (8 + 2 = 10), or combine Star Period 9 and Star Period 1 (9 + 1 = 10).
Rule 3 — He Tu Generative Date Chart (Hợp Sinh Thành Khóa): The four time pillars combine Gua Qi 8 and Gua Qi 3 (difference of 5, uniting Yang creation and Yin completion of Yin Wood (He Tu 3–8 Companion Wood)) while ensuring the Day and Hour Gua Qi produce Inward (Sinh Nhập) or assist (Tỷ Hòa) the Sitting Mountain and Householder's Natal Pillar.

FIELD AUDIT #1 · MASTER UNG KHIEM ARCHIVE

Case Study 1: Logistics & EV Manufacturing Plant in Hai Phong — Sitting Heng #32 (167.2° Yao 5) Facing Yi #42 (116.5° Yao 5)

Heavy industry, logistics fleets, and electric mobility thrive on the arousal of Zhen Thunder ☳. When I audited a 12-hectare EV component and logistics park in Hai Phong, we set the main administrative and assembly spine at 167.2° (Bính Mountain, Yao 5 of #32 Thunder Wind Heng 雷風恒 ䷟: Gua Qi 8 Wood, Star Period 9 Direct Spirit) and angled the primary freight gate and retention lake toward the Southeast Thìn sector at 116.5° (Yao 5 of #42 Wind Thunder Yi 風雷益 ䷩: Gua Qi 2 Fire, Star Period 9). Look at the classic 'Thunder and Wind mutually reinforcing' (Lôi Phong tương bạc) coupling: Sitting Gua Qi 8 + Gate Gua Qi 2 = 10 (Sum of Ten), Wood 8 generates Fire 2, and both positions share Timely Period 9! Plant output exceeded targets by 42% in its first year.

FIELD AUDIT #2 · MASTER UNG KHIEM ARCHIVE

Case Study 2: Penthouse Residence in Thu Thiem — Tapping #16 Yu (143.8° Yao 4) & #48 Jing (88.5° Yao 5)

Even in a high-rise penthouse where exterior walls are fixed, internal Da Gua angular alignment works wonders. A tech entrepreneur in Thu Thiem suffered from chronic insomnia and stalled product launches because his bed and study desk sat on a dead line between Thìn and Tỵ. From the central Taiji of the penthouse, we placed his executive desk at 143.8° (Yao 4 of #16 Thunder Earth Yu 雷地豫 ䷏: Gua Qi 8 + Star Period 2 = built-in 8+2=10 Sum of Ten, 'Source of enthusiasm, great achievements') and positioned a circulating quartz water fountain on the eastern balcony at 88.5° (Yao 5 of #48 Water Wind Jing 水風井 ䷯, 5th Gen of Zhen: 'Cold crystal spring water'). Both sleep quality and product velocity rebounded within six weeks.

Measure Your Exact Zhen Group ☳ Thunder Hexagram & 384-Yao Line on Your Floor Plan

Want to verify which of the 64 Early Heaven Hexagrams and 384 individual lines your home, villa, or corporate headquarters sits on—and whether it locks into Period 9 Direct and Indirect Spirit resonance? Launch Master Ung Khiem's interactive tools now:

☯️ Xuan Kong Da Gua Hub 🧭 Launch Luo Pan Pro (64 Hexagrams & 384 Yao) 🏠 3D Home Feng Shui Simulator

12. Frequently Asked Questions (FAQ) & Classical Bibliography on the Zhen Group (Thunder ☳ · Chấn Cung)

1. Which 8 hexagrams belong to the Zhen Group (Thunder ☳ · Chấn Cung) in Xuan Kong Da Gua?

Two complementary sets define this palace. In the Jing Fang 8-Palace transformation lineage (Bát Cung Kinh Phòng), the 8 hexagrams of the Zhen Group (Thunder ☳ · Chấn Cung) are #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #46 Địa Phong Thăng (䷭), #48 Thủy Phong Tỉnh (䷯), #28 Trạch Phong Đại Quá (䷛), #17 Trạch Lôi Tùy (䷐). On the San Yuan 360° Upper-Trigram Compass Ring, the 8 hexagrams sharing Zhen ☳ as their Upper (Outer) Trigram—all carrying Gua Qi 8 (Yin Wood (He Tu 3–8 Companion Wood))—are #51 Chấn Vi Lôi (䷲), #16 Lôi Địa Dự (䷏), #40 Lôi Thủy Giải (䷧), #32 Lôi Phong Hằng (䷟), #34 Lôi Thiên Đại Tráng (䷡), #54 Lôi Trạch Quy Muội (䷵), #55 Lôi Hỏa Phong (䷶), #62 Lôi Sơn Tiểu Quá (䷽). Notice that the first four hexagrams (Steps 0, 1, 2, and 3) belong to both sets simultaneously!

2. Why do the first 4 hexagrams of the Zhen Palace carry Gua Qi 8, while the last 4 change their Gua Qi?

Look at the Outer Trigram. In San Yuan Xuan Kong Da Gua, a hexagram's spatial Gua Qi (1–9) is governed 100% by its Upper (Outer) Trigram. During Jing Fang's first three line transformations (Pure Root #51, 1st Gen #16, 2nd Gen #40, and 3rd Gen #32), only the bottom three lines (Lower Trigram) change, leaving Zhen ☳ unchanged on top with Gua Qi 8. Once the transformation climbs into the 4th and 5th lines (4th Gen #46, 5th Gen #48, Wandering Soul #28, and Returning Soul #17), the Upper Trigram changes, shifting their compass Gua Qi while preserving their Zhen Palace ancestral soul.

3. Which hexagram in the Zhen Group (Thunder ☳ · Chấn Cung) is the strongest Sitting Mountain in Period 9 (2024–2043)?

One hexagram stands supreme. The 3rd-Generation Lower-Cycle Parent Hexagram #32 Lôi Phong Hằng (雷風恒 ䷟) at Bính – Ngọ (163.125°–168.750°) carries Star Period 9 (Right Assistant / You Bi) and Gua Qi 8. Because its Upper and Lower Trigrams are in total 3-line Yin-Yang opposition, it acts as the reigning Period 9 Direct Spirit (Chính Thần)—ideal for the Sitting Mountain spine, high terrain backing, executive suite, and Master Bed.

4. Which hexagram in the Zhen Group (Thunder ☳ · Chấn Cung) is best for the Main Gate or Water Mouth in Period 9?

Tap the Pure Root! The doubled hexagram #51 Chấn Vi Lôi (震為雷 ䷲) at Thìn (135.000°–140.625°) carries Star Period 1 (Greedy Wolf / Tan Lang) and Gua Qi 8. In Period 9, Star Period 1 forms Sum of Ten (1 + 9 = 10) with the ruling period, making #51 Chấn Vi Lôi the crown Indirect Spirit (Linh Thần) for main gates, water mouths, pools, and road junctions.

5. How do I pair the Zhen Group (Thunder ☳ · Chấn Cung) using Sum of Ten (He Shi) and Difference of Five (He Sheng Cheng)?

Two mathematical locks govern pairing. For Sum of Ten (He Shi 合十), pair any Upper-Zhen hexagram (Gua Qi 8) with any hexagram from the Xun Group ☴ (Gua Qi 2 Fire · 8 + 2 = 10) so their Gua Qi numbers add up to 10. For He Tu Generative Difference of Five (He Sheng Cheng 合生成), pair Gua Qi 8 with the Li Group ☲ (Gua Qi 3 Wood · 8 – 3 = 5) so their Gua Qi numbers differ by 5 and unite within Yin Wood (He Tu 3–8 Companion Wood).

6. How do I avoid Void Lines (Không Vong) when aligning a building to the Zhen Group (Thunder ☳ · Chấn Cung)?

Never set a centerline on a seam. Each hexagram spans 5.625° and each individual yao line spans 0.9375°. Keep your structural sitting-facing thread at least ±0.75° away from 24-Mountain and 8-Palace borders (Great Void / Đại Không Vong) and at least ±0.45° away from the 5.625° inter-hexagram borders (Small Void / Tiểu Không Vong), aiming squarely for the middle of Yao 2 or Yao 5.

7. Can I apply the Zhen Group (Thunder ☳ · Chấn Cung) in an apartment where I cannot change the building's exterior orientation?

Yes—through Micro-Taiji angular distribution. Stand at the center of your apartment or main living room with a San Yuan Luo Pan and locate where #32 Lôi Phong Hằng, #51 Chấn Vi Lôi, and #40 Lôi Thủy Giải fall. Place your bedhead, executive desk, induction stove, and indoor water feature onto those exact 0.9375° Red Jewel Lines, then switch the formation on using a resonant Da Gua Date Selection chart.

8. How do I select an auspicious Xuan Kong Da Gua date for a Zhen Group (Thunder ☳ · Chấn Cung) property?

Match the Four Pillars of time to the Sitting Mountain's Gua Qi. Convert the Year, Month, Day, and Hour stems and branches into their 64-hexagram Da Gua equivalents, and choose a chart whose four pillars carry Gua Qi 8 (Pure One Qi), Gua Qi 2 (Sum of Ten), or Gua Qi 3 (He Tu Difference of Five), while avoiding annual Thái Tuế and Tam Sát clashes on the Sitting degree.

Classical Sources & Academic References

Grandmaster Yang Yun Song (楊筠松, Tang Dynasty), Qing Nang Ao Yu (青囊奧語 · Green Satchel Mystery Words) & Tian Yu Jing (天玉經 · Heavenly Jade Classic).
Grandmaster Jiang Da Hong (蔣大鴻, Ming–Qing Dynasty), Di Li Bian Zheng (地理辨正 · Rectifying the Canon of Earth Principles).
Jing Fang (京房, Western Han Dynasty), Jing Shi Yi Zhuan (京氏易傳 · Commentary on the Eight-Palace I Ching Transformations).
Shao Yong (邵雍, Northern Song Dynasty), Huangji Jingshi Shu (皇極經世書 · Supreme Principles Governing the World — Fu Xi 64-Hexagram Square & Circular Diagrams).
Anonymous (Ming–Qing San Yuan Transmission), Yu Han Tong Mi (玉函通秘 · Jade Casket Mystery of Xuan Kong Da Gua).
Zeng Zi Nan (曾子南), San Yuan Xuan Kong Da Gua Di Li Jiao Cai (三元玄空大卦地理教材 · Three-Cycle Xuan Kong Da Gua Geomancy Compendium).
Imperially Commissioned Qianlong Compendium (1741), Xie Ji Bian Fang Shu (協紀辨方書 · Treatise on Harmonizing Times and Distinguishing Directions).