Hou Tian Yang Zhai Bi Ying

The Taigong Yun'ao Art (太公蘊奧術) — literally 'Taigong's Art of Hidden Profundity' — traces its origins to the legendary HuangShi Gong (黃石公) of the Qin-Han transition period, the same figure credited with transmitting the San Lue (Three Strategies) to Zhang Liang. During the early Qing Dynasty, a mysterious Daoist elder known only as Hu Laoxian (胡老仙師) took lodging at the Li family residence in Jimo (即墨), Shandong province. Recognising the Li family's moral character, Hu Laoxian transmitted the complete art exclusively to the Li clan through a single-line transmission (單傳), establishing a strict rule that each generation could teach only one successor.

For five generations, the Li family guarded the art in absolute secrecy. Li Hushan (李胡山), born in 1918 with the given name Mingge (明閣) and courtesy name Hushan (胡山), became the fifth-generation sole heir. In 1945, he migrated to Taiwan with the Nationalist government, bringing the art across the Taiwan Strait. Witnessing the decline of authentic Feng Shui knowledge and the proliferation of confused teachings, Li Hushan made the momentous decision to break the single-transmission tradition and teach publicly for the first time. His 294-page treatise, published in 2001, codifies the entire system for posterity.

The generation verse (呼風喚雨，山海奇觀 — 'Summoning wind and rain, wondrous spectacles of mountains and seas') encapsulates the art's ambition: to read and harness the natural forces that govern human dwelling spaces. The system's name 'Hou Tian' (後天, Post-Heaven) distinguishes it from Pre-Heaven (先天) theoretical systems, emphasising practical, observable reality over abstract metaphysics.

The Five Classifications (五法分類) system is the foundational innovation of the Hou Tian Pai, providing a typological framework that no other Feng Shui school possesses. Every structure in the built environment — whether a single-story farmhouse, a 30-story apartment tower, a Daoist temple, a manufacturing plant, or an ancestral tomb — must first be classified into one of five categories before any analysis can proceed. Each classification determines not only the analytical method but also the type of qi being cultivated, the primary reference point for measurement, and the associated Five Element quality.

The five types are: Jing (靜, Still House) — detached single-story dwellings associated with Metal (金) and Birth-Prosperity Qi (生旺之氣), analysed with the room as host; Lou (樓, Multi-Story Building) — multi-level structures associated with Wood (木) and Birth-Prosperity Qi, analysed with the star as host; Shen (神, Temple) — sacred spaces associated with Fire (火) and Sha-Prosperity Qi (煞旺之氣), analysed through the flipping trigram method; Gong (工, Factory/Commercial) — industrial and processing facilities associated with Water (水), analysed through the BaGua trigrams; and Feng (風, Yin House) — burial sites associated with Earth (土) and Gate-Prosperity Qi (關旺之氣), analysed through Nine Stars communication.

This classification is not arbitrary — it reflects a deep understanding of how different building typologies interact with environmental qi. A temple that receives inauspicious stars as divine power would be catastrophically misanalysed if assessed using residential methods. Similarly, a multi-story building where each floor has a different Dwelling Master Star cannot be treated as a simple ground-level house. The Five Classifications prevent these fundamental errors.

Within the Jing (靜, Still House) classification, Li Hushan identifies seven distinct sub-types of single-story dwellings, each with its own assessment nuances. These seven types reflect the full range of traditional Chinese residential architecture: (1) Detached courtyard houses (獨院平房) — the standard single-family dwelling with a walled courtyard; (2) Siheyuan four-sided compounds (四合院) — the classic Beijing-style courtyard with rooms on all four sides; (3) Sanheyuan three-sided compounds (三合院) — courtyard with rooms on three sides, common in southern China; (4) Tiled-roof houses (瓦房) — standard brick-and-tile construction; (5) Thatched houses (草房) — rural straw-roofed dwellings; (6) Cave dwellings (窯洞) — earth-carved homes common in Shaanxi and Shanxi provinces; and (7) Boat houses (船屋) — floating or waterside dwellings found in fishing communities.

All seven sub-types share the same analytical foundation: the Earthly Branches (地支) serve as the primary reference system, and assessment prioritises the external water configuration (外部水局) and the sitting-facing axis (坐向). The Dwelling Master Star (宅主星) is determined from the sitting mountain position. However, each sub-type requires specific adaptations — for example, cave dwellings have only one exposed face, so the door direction carries exceptional weight, while siheyuan compounds must account for the qi dynamics of the enclosed central courtyard.

The distinction between Jing and Lou classifications is critical: a Jing house uses Earthly Branches and takes the room as host (以房為主), while a Lou building uses Heavenly Stems and takes the star as host (以星為主). Misapplying Lou methods to a single-story house — or vice versa — produces fundamentally incorrect results. The seven sub-types ensure that even within the Jing category, the practitioner accounts for structural differences that affect qi flow.

The Sixteen-Direction System (十六方位系統) is one of the Hou Tian Pai's most distinctive innovations. While standard Ba Zhai analysis uses only 8 directions (45 degrees each) and the standard Luopan employs 24 mountains (15 degrees each), the Hou Tian Pai divides the compass into 16 sectors of 22.5 degrees each. This precision level sits between the coarse 8-direction model and the fine 24-mountain model, providing what Li Hushan considered the optimal balance between analytical precision and practical applicability for dwelling assessment.

The sixteen directions are organised into four groups of four: Si Zheng (四正, Four Cardinals) — 壬子 (N, 0 degrees), 甲卯 (E, 90 degrees), 丙午 (S, 180 degrees), 庚酉 (W, 270 degrees); Si Yu (四隅, Four Corners) — 艮寅 (NE, 45 degrees), 巽巳 (SE, 135 degrees), 坤未 (SW, 225 degrees), 乾亥 (NW, 315 degrees); Si Yin Gan Bian Gong (四陰干變宮, Four Yin-Stem Transforming Palaces) — 癸丑 (NNE, 22.5 degrees), 乙辰 (ESE, 112.5 degrees), 丁未 (SSW, 202.5 degrees), 辛戌 (WNW, 292.5 degrees); and Si Yang Gan Zuo Lu (四陽干坐祿, Four Yang-Stem Sitting Prosperity) — 寅甲 (ENE, 67.5 degrees), 巳丙 (SSE, 157.5 degrees), 庚申 (WSW, 247.5 degrees), 亥壬 (NNW, 337.5 degrees).

Each direction is named by combining two characters from the 24-mountain system, indicating which pair of traditional mountains it straddles. For example, 壬子 straddles the 壬 and 子 mountains of the standard 24-mountain compass. The four group names reveal the underlying logic: the Cardinals and Corners correspond to the standard 8 trigram directions, while the Yin-Stem and Yang-Stem groups fill the intermediate positions, each carrying specific Five Element and Stem-Branch properties that inform the wandering star analysis.

The Dwelling Master Star (宅主星) concept is perhaps the most important theoretical innovation of the Hou Tian Pai, distinguishing it from all other Ba Zhai schools. In standard Eight Mansions analysis, the sitting trigram determines a fixed pattern of eight wandering stars, and the Fu Wei (伏位, Resting Position) — which always falls on the sitting direction itself — is treated as the primary reference. Li Hushan's system, however, introduces the concept of a 'useful god' (用神) for each dwelling, analogous to the crucial 'useful god' concept in BaZi (Four Pillars) destiny analysis.

The Main Star is determined by the intersection of two factors: the sitting direction and the door direction. With 8 possible sitting trigrams and 8 possible door directions, there are 64 possible combinations (八宅八方 = 六十四組合), each yielding a specific Main Star. This Main Star is NOT the same as the Fu Wei; it is the specific wandering star that arrives at the door position when the wandering star sequence is deployed from the sitting trigram. The Main Star functions as the 'useful god' of the dwelling — if it is an auspicious star (生氣, 天醫, 延年, or 伏位), the dwelling receives Birth-Prosperity Qi (生旺之氣) at its mouth, and the house is fundamentally auspicious. If the Main Star is inauspicious (禍害, 六煞, 五鬼, or 絕命), the dwelling receives destructive qi.

This innovation has profound practical implications. Two houses with identical sitting directions but different door positions will have different Main Stars and therefore different fundamental fortunes. Standard Ba Zhai analysis, which derives everything from the sitting trigram alone, cannot make this distinction. The Main Star concept explains why neighbouring houses with the same orientation can have vastly different fortunes — a puzzle that has long troubled Ba Zhai practitioners.

The Da You Nian Method (大遊年法, Great Wandering Year Method) is the mathematical engine of the Eight Mansions system, and the Hou Tian Pai preserves and applies it with particular rigour. The method derives the wandering star for each of the eight directions relative to a given sitting trigram, producing the complete Eight Mansions chart. The eight mnemonics (歌訣) listed above encode the entire system in a compact, memorisable form that practitioners have transmitted orally for centuries.

Each mnemonic begins with the trigram name and then lists the wandering star for each subsequent direction in sequence. For example, '乾六天五禍絕延生' means: for a Qian (乾) sitting house, the directions in sequence receive Liu Sha (六煞), Tian Yi (天醫), Wu Gui (五鬼), Huo Hai (禍害), Jue Ming (絕命), Yan Nian (延年), and Sheng Qi (生氣). The first position is always Fu Wei (伏位) at the sitting direction itself, which is implied and not listed in the mnemonic. The shorthand characters are: 六=六煞, 天=天醫, 五=五鬼, 禍=禍害, 絕=絕命, 延=延年, 生=生氣.

The underlying mathematical logic is XOR (exclusive-or) flipping of the three yao (爻) lines of each trigram. When comparing the sitting trigram to any direction trigram, one counts which of the three yao lines differ. The pattern of differing lines determines the wandering star: if only the top yao differs, the star is Sheng Qi (生氣); if only the middle yao differs, it is Wu Gui (五鬼); if only the bottom yao differs, it is Huo Hai (禍害); and so forth for all eight possible combinations including the identity (Fu Wei, no yao differ). This binary logic produces a perfectly symmetric 8x8 matrix where the star for A looking at B always equals the star for B looking at A.

The He Tu Floor System (河圖樓層法) is the Hou Tian Pai's method for analysing multi-story buildings (Lou, 樓 classification). Based on the ancient He Tu (River Map) generation numbers, this system assigns a Five Element quality to each floor of a building according to a cyclical pattern. The He Tu pairs are: 1-6 = Water (水), 2-7 = Fire (火), 3-8 = Wood (木), 4-9 = Metal (金), 5-10 = Earth (土). These pairs repeat every five or six floors: floors 1, 6, 11, 16, 21, 26 are all Water; floors 2, 7, 12, 17, 22, 27 are all Fire; and so forth in an infinite ascending cycle.

The practical significance is that each floor has a specific Five Element nature that interacts with the building's sitting direction and the occupant's personal trigram. A floor whose element generates or supports the occupant's element is auspicious; a floor whose element clashes with or drains the occupant's element is inauspicious. For example, if an occupant's personal trigram belongs to the Wood element, floors 1, 6, 11 (Water, which generates Wood) and floors 3, 8, 13 (Wood, which is same element) are most favourable, while floors 4, 9, 14 (Metal, which destroys Wood) are most harmful.

Crucially, in the Lou classification, each floor has its own Dwelling Master Star (宅主星) because each floor's element modifies the sitting-door star interaction. Two apartments on different floors of the same building, both facing the same direction with the same door position, can have different fortunes because their floor elements differ. This is a refinement that standard Ba Zhai completely lacks — it treats all floors of a building identically, which Li Hushan considered a serious analytical error.

The concept of Penetrating Well Intercourse (貫井交媾) is one of the Hou Tian Pai's most original contributions to Feng Shui theory, addressing a challenge that traditional systems never confronted: the vertical qi dynamics of multi-story buildings. The 'penetrating well' (貫井) refers to the stairwell or elevator shaft — the vertical void that runs through a building from bottom to top. In the Hou Tian Pai's analysis, this shaft functions as a vertical qi channel, analogous to the spinal column (脊柱) in the human body, through which qi flows between floors.

The term 'intercourse' (交媾) — borrowed from San He Feng Shui vocabulary where it describes the meeting of mountain and water dragons — here describes the mixing and interaction of qi between different floors via the stairwell or elevator shaft. Each floor has its own Five Element quality (determined by the He Tu Floor System), and the penetrating well allows these different elemental energies to interact. A Water-element floor (1st, 6th) directly connected by a stairwell to a Fire-element floor (2nd, 7th) creates a Water-Fire clash through the vertical channel, potentially causing problems for occupants of both floors.

The position of the stairwell or elevator shaft within the building's floor plan is therefore a matter of great importance. If the penetrating well falls in an auspicious sector (as determined by the wandering star analysis), it amplifies positive qi circulation between floors. If it falls in an inauspicious sector — particularly the Wu Gui (五鬼) or Jue Ming (絕命) position — it becomes a conduit for negative qi that affects every floor it connects. Modern high-rise buildings with centrally located elevator banks require careful assessment of this factor.

The Three Essentials (陽宅三要) — Door (門), Master Bedroom (主), and Kitchen/Stove (灶) — represent the most critical triad in yang dwelling assessment. This framework, classically attributed to Zhao Jiufeng (趙九峰) of the Qing Dynasty in his work Yang Zhai San Yao (陽宅三要), is adopted and extended by the Hou Tian Pai as a core diagnostic tool. The door is the qi mouth (氣口) through which external energy enters; the master bedroom is the human element (人元) where the occupant restores their vitality; the kitchen stove is the life-nourishing element (養命) that sustains the family's health and wealth.

The fundamental rule is that the Five Elements of these three positions must form a generative cycle: the Door generates the Master Bedroom, the Master Bedroom generates the Kitchen, and the Kitchen generates the Door. This creates a self-reinforcing positive cycle of qi circulation within the dwelling. When all three are in auspicious wandering star positions and their Five Elements are mutually generative, the house is considered fully auspicious (全宅大吉). When one of the three falls in an inauspicious position, problems manifest specifically in that domain — for example, an inauspicious kitchen may produce health and financial problems, while an inauspicious master bedroom may cause relationship or sleep disorders.

When all three are in positions whose Five Elements are mutually destructive (相剋), the house is fundamentally troubled: the household experiences continuous unrest and recurring disasters. The Hou Tian Pai refines this analysis by using the 16-Direction System to determine the precise wandering star at each of the three positions, providing finer diagnostic resolution than the standard 8-direction Ba Zhai approach.

The Twenty-Four Door Types (二十四門型) system classifies every possible door position into one of 24 named types — 12 auspicious and 12 inauspicious — based on the wandering star at the door direction relative to the sitting trigram. This classification goes beyond the simple auspicious/inauspicious labels of standard Ba Zhai analysis, providing specific named effects for each door configuration that allow the practitioner to predict the exact nature of fortune or misfortune the dwelling will experience.

The twelve auspicious door types are: Guan Jue (官爵) — rank advancement and achieving prominence; Guan Gui (官貴) — official prosperity and smooth career; Fu De (福德) — virtue, blessings, and family prosperity; Sheng Wang (生旺) — population growth and vitality; Xing Long (興隆) — business prosperity and smooth affairs; Wang Can (旺蠶) — livestock flourishing and side businesses prospering; Jin Bao (進寶) — wealth flowing in and full treasury; Rong Chang (榮昌) — family glory and widespread renown; Qin Yin (親姻) — happy marriages and harmonious unions; Huan Le (歡樂) — family joy and continuous celebrations; Wang Cai (旺財) — flourishing wealth, both direct and indirect; Fu Lu (福祿) — double blessings of fortune and longevity.

The twelve inauspicious door types are: Tian Ji (天疾) — heavenly illness and health deterioration; Lao Song (牢訟) — imprisonment and endless litigation; Hei Sha (黑煞) — dark evil encroachment; Heng Huo (橫禍) — unexpected calamity and accidental disaster; Xing Di (刑地) — punishment, injury, and ruin; Di Qi (地泣) — earth weeps, household unrest; An Hai (暗害) — hidden harm and betrayal; Dian Kuang (顛狂) — mental disorder and madness; Zao Wang (早往) — early death and shortened lifespan; Chang Yin (娼淫) — depravity and moral degradation; Si Jue (四絕) — cut off from all sides, no family support; Gu Gua (孤寡) — loneliness, widowhood, and solitude.

The Purple-White Flying Stars (紫白飛星) system is the Hou Tian Pai's method for time-based qi analysis, calculating the Nine Star influences for any given year, month, day, and hour. This temporal dimension complements the spatial analysis of the wandering stars, creating a comprehensive space-time assessment framework. The system uses nine stars numbered 1-9, each with specific element and auspiciousness qualities: 1-White (Water, auspicious), 2-Black (Earth, inauspicious), 3-Jade (Wood, inauspicious), 4-Green (Wood, semi-auspicious), 5-Yellow (Earth, most inauspicious), 6-White (Metal, auspicious), 7-Red (Metal, inauspicious), 8-White (Earth, most auspicious), 9-Purple (Fire, auspicious).

The annual formula derives the center star for any Gregorian year: sum all digits of the year, subtract 1, then subtract the result from 10. For 2026: 2+0+2+6=10, 10-1=9, 10-9=1, so 1-White enters the center in 2026. The monthly formula depends on the year's Earthly Branch: for 子午卯酉 years, start from 8-White; for 寅申巳亥 years, start from 2-Black; for 辰戌丑未 years, start from 5-Yellow. The mnemonic '子午卯酉八白起，寅申巳亥二黑求，辰戌丑未五黃中' encodes this completely.

The daily formula divides the year into six periods based on solar terms: Winter Solstice to Spring Start uses star 1 forward; Rain Water to Pure Brightness uses star 7 forward; Grain Rain to Grain in Ear uses star 4 forward; Summer Solstice to Autumn Start uses star 9 reverse; End of Heat to Cold Dew uses star 3 reverse; Frost Descent to Heavy Snow uses star 6 reverse. The hourly formula is mathematical: after the Winter Solstice, (3 x DayStar - 3 + HourOrdinal) mod 9; after the Summer Solstice, (3 x DayStar + 1 - HourOrdinal) mod 9. Together, these four layers produce a precise temporal energy signature for any moment.

The Hou Tian Pai's room placement methodology integrates the wandering star chart with specific guidelines for each room type, producing actionable recommendations for interior layout. The system identifies two categories of financial positions: the Bright Financial Position (明財位), which is the diagonal corner from the main entrance in the living room and must be well-lit, backed by a solid wall, and kept clean and stable; and the Dark Financial Position (暗財位), determined by the Purple-White Flying Star system's current growth and prosperity positions, which shifts with annual and monthly star movements.

For the master bedroom, the optimal positions are the Yan Nian (延年) or Tian Yi (天醫) wandering star sectors. Yan Nian promotes spousal harmony and longevity; Tian Yi promotes health and recovery from illness. Per I Ching principles, the northwest is the father's position and the southwest is the mother's position, adding a layer of directional significance based on the occupant's role in the family. For the kitchen, the principle is 'sit on sha, face fortune' (坐煞向吉) — the stove's body sits in an inauspicious sector while its mouth faces an auspicious direction. East and southeast directions are preferred because Wood feeds Fire. Six kitchen taboos must be observed: stove visible from the entrance (drains wealth), stove directly facing a faucet (Water-Fire clash), beam pressing on stove, mirror facing stove, stove under a staircase, and bedroom directly above the stove.

The bathroom should be placed in inauspicious sectors to drain negative energy, but must never occupy the center palace (中宮), as this pollutes the dwelling's core. The north direction is also problematic because prevailing winds can carry bathroom odors inward. Bed orientation should follow geomagnetic alignment (south-north preferred), with the headboard against a solid wall for symbolic backing. The bed must allow visibility of the door and window, and the head must not face west (associated with death in Chinese symbolism).

Temple assessment (廟宇風水) represents one of the most distinctive aspects of the Hou Tian Pai system. Under the Shen (神) classification, sacred spaces operate on principles that are diametrically opposite to those governing residential dwellings. While a house seeks Birth-Prosperity Qi (生旺之氣) — the auspicious wandering stars — at its door, a temple seeks Sha-Prosperity Qi (煞旺之氣) — the inauspicious wandering stars. The temple transforms destructive sha energy into divine authority (神威), channelling what would be harmful to human residents into spiritual power.

The primary star for temple assessment is Lian Zhen (廉貞), the Five Ghost (五鬼) star. In residential analysis, Wu Gui is among the most feared inauspicious stars, associated with fire, theft, spirit disturbance, and financial loss. In temple analysis, however, this same energy is harnessed as divine authority. The logic is that a deity requires fierce, powerful energy — not gentle, nurturing energy — to maintain its spiritual jurisdiction. A temple built on 'auspicious' residential principles would actually weaken its divine presence.

The Hou Tian Pai prescribes a systematic nine-step process for temple assessment: (1) measure the main hall's sitting direction with a Luopan; (2) determine the sitting trigram in the Post-Heaven Bagua; (3) use the flipping trigram method (反卦法) to derive sha stars for each direction; (4) confirm the main door is at an inauspicious star position (Sha-Prosperity Qi at door); (5) check the Four Sacred Beasts arrangement — backing mountain behind, bright hall in front, Green Dragon left, White Tiger right; (6) assess water mouth positions including release ponds and drainage; (7) confirm the main hall is the tallest structure in the compound; (8) check the central axis symmetry and north-south alignment; (9) assess the altar placement — against a wall, facing the door, with proper deity hierarchy maintained.

The Yin House Method (陰宅法) addresses burial site Feng Shui under the Feng (風) classification, the fifth and final category in the Five Classifications system. Yin houses operate on Gate-Prosperity Qi (關旺之氣) — a third type of qi distinct from both the Birth-Prosperity Qi of residences and the Sha-Prosperity Qi of temples. The assessment method uses San He (三合) principles, specifically the Four Major Water Mouths (四大水口), to determine the optimal sitting-facing direction for the burial site. The distinction between Mountain Dragons (山龍) and Water Dragons (水龍) is critical: mountain terrain follows mountain dragon principles, while flat or riverine terrain follows water dragon principles.

The system identifies four fundamental acupoint forms (穴形): Wo (窩, Cavity/Nest) — a Yang-natured form with a flat front, raised back, and two arms embracing like a golden basin, also called an open-mouth acupoint; Qian (鉗, Pincer/Tongs) — a Yang-natured form with two arms extending forward like chopsticks, also called a tiger-mouth acupoint; Ru (乳, Breast) — a Yin-natured form with two arms spread and a rounded central protrusion, also called a hanging-breast acupoint; Tu (突, Prominence) — a Yin-natured form showing a raised mound in otherwise flat terrain, particularly prized in flat ground landscapes. The practitioner must correctly identify the acupoint form before determining the precise burial position.

The Golden Well (金井) is the circular deep hole at the center of the coffin platform, serving as the conduit between the yin realm of the deceased and the yang earth qi. When excavating the Golden Well, the soil colour and texture must match the soil at the incoming dragon's entry point (入首龍) — a discrepancy indicates the qi channel is disrupted or the acupoint is false. The warming pit ceremony (暖坑), traditionally performed by the eldest son lying in the Golden Well, consecrates the site. Different trigram sectors of the burial site affect different sons: the left side (Zhen/Xun trigrams) governs the 1st, 4th, and 7th sons; the front (Kan trigram) governs the 2nd, 5th, and 8th sons; the right side (Gen trigram) governs the 3rd, 6th, and 9th sons.

The final chapter of the Hou Tian Yang Zhai Bi Ying presents case studies that demonstrate the system's practical application and verification methodology. Li Hushan emphasised that Feng Shui theory without empirical verification is mere academic speculation, while empirical observation without theoretical grounding is superstition. The case study approach bridges this gap by applying the system's principles to real structures and comparing predictions against documented outcomes.

The Forbidden City (北京故宮) case study illustrates the Hou Tian Pai's principles at their grandest scale. The imperial palace complex demonstrates a perfect Post-Heaven Bagua layout: a strict north-south central axis; yellow roofs representing Earth element (symbolising imperial authority); red walls representing Fire element (Fire generates Earth, supporting imperial power); the Jin Shui River (Golden Water River) flowing east to west through the complex (embodying the principle 'mountains govern population, water governs wealth'). The Tai He Dian (太和殿, Hall of Supreme Harmony) occupies the highest position in the entire complex, functioning as the emperor's throne in the landscape — the ultimate seat of power at the apex of a carefully orchestrated qi architecture.

The Dalian Yin House Case (大連陰宅案例) provides striking evidence for the descendants mapping principle. An ancestral burial site had its due-east mountain — corresponding to the Zhen (震) trigram, which governs the eldest son — severely damaged by quarrying operations that blasted the mountain for stone extraction. Following this destruction, the eldest son's daughter was born mute and his grandson was born deaf, while the second son's family experienced no such problems and continued to thrive. The Zhen trigram sector governs the 1st, 4th, and 7th sons; the damage fell precisely in this sector and affected precisely this line of descendants, confirming the mapping principle with remarkable specificity. These and other case studies form the evidentiary foundation upon which the Hou Tian Pai's credibility rests.