\r司天在泉左右间气图\pt13a29.bmp\r
司天歌
子午少阴为君火，丑未太阴临湿土，寅申少阳相火王，卯酉阳明燥金所，辰戌太阳寒水边，巳亥
厥阴风木主，初气起地之左间，司天在泉对面数。
司天、在泉、四间气者，客气之六步也。凡主岁者为司天，位当三之气。司天之下相对
者为在泉，位当终之气。司天之左为天之左间，右为天之右间。在泉之左为地之左间，右
为地之右间。每岁客气始于司天前二位，乃地之左间，是为初气，以至二气、三气而终于在泉之六气，每
气各主一步。然司天通主上半年，在泉通主下半年，故又曰岁半以前，天气主之，岁半以后，地气主之也。
五营运大论曰∶天地者，万物之上下也。左右者，阴阳之道路也。诸上见厥阴，左少
阴，右太阳；见少阴，左太阴，右厥阴；见太阴，左少阳，右少阴；见少阳，左阳明，右太阴；见
阳明，左太阳，右少阳；见太阳，左厥阴，右阳明，所谓面北而命其位也。面北命位者，谓司
天在上，位在南方，面北而命其左右，则东南为司天之右间，西南为司天之左间也。又曰∶
何谓下？曰∶厥阴在上则少阳在下，左阳明，右太阴；少阴在上则阳明在下，左太阳，右少
阳；太阴在上则太阳在下，左厥阴，右阳明；少阳在上则厥阴在下，左少阴，右太阳；阳明在
上则少阴在下，左太阴，右厥阴；太阳在上则太阴在下，左少阳，右少阴，所谓面南而命其位
也。面南命位者，谓在泉在下，位在北方，面南而命其左右，则东北为在泉之左间，西北为
在泉之右间也。上者右行，自西南而降，下者左行，自东北而升，左右周天，余而复会。故
上下相遘，天地相临，而变化逆顺，由兹生矣。虽同类相和、气化相生者谓之顺，异类相临、
气化相制者谓之逆；然有气虽同类而亦为病者，以相火临于君火，为不当位故也。故六微
旨大论曰∶君位臣则顺，臣位君则逆，逆则病近害速，顺则病远害微，所谓二火者是也。此
当与前五运太少齐兼化图解参看。
六微旨大论曰∶天道六六之节，盛衰何也？曰∶上下有位，左右有纪。故少阳之右，阳
明治之；阳明之右，太阳治之，太阳之右，厥阴治之；厥阴之右，少阴治之；少阴之右，太阴治
之；太阴之右，少阳治之。此言客气阴阳之次序也。
司天歌诀
子年和午年，少阴君火（少阴心包经的君火之气）主司；丑年和未年，太阴湿土（太阴脾经的湿土之气）临御；寅年和申年，少阳相火（少阳三焦胆经的相火之气）旺盛；卯年和酉年，阳明燥金（阳明大肠胃经的燥金之气）当令；辰年和戌年，太阳寒水（太阳膀胱肾经的寒水之气）居边；巳年和亥年，厥阴风木（厥阴肝经的风木之气）主持。初气始于地之左间，从司天和在泉相对的位置开始推算。
所谓司天、在泉、四间气，是客气（每年变化的气候之气）的六个阶段。凡是主管全年的称为司天，位于第三步气（三之气）。与司天相对下方的称为在泉，位于最后一步气（终之气）。司天的左侧为天之左间气，右侧为天之右间气。在泉的左侧为地之左间气，右侧为地之右间气。每年的客气始于司天前两位，即地之左间气，这称为初气，依次至二气、三气，最终到在泉的六气，每气各主管一个阶段。然而司天总管上半年，在泉总管下半年，所以又说岁半以前由天气主管，岁半以后由地气主管。
《五营运大论》说：天地，是万物的上下方。左右，是阴阳运行的道路。凡是上面见到厥阴风木，左边是少阴君火，右边是太阳寒水；见到少阴君火，左边是太阴湿土，右边是厥阴风木；见到太阴湿土，左边是少阳相火，右边是少阴君火；见到少阳相火，左边是阳明燥金，右边是太阴湿土；见到阳明燥金，左边是太阳寒水，右边是少阳相火；见到太阳寒水，左边是厥阴风木，右边是阳明燥金。这就是所谓的“面北而命其位”（面向北方来确定方位）。所谓“面北命位”，是指司天在上，方位在南面，人面向北方来定左右，那么东南方就是司天的右间气，西南方就是司天的左间气。
又问：什么叫做下（在泉）？回答说：厥阴风木在上，则少阳相火在下，左边是阳明燥金，右边是太阴湿土；少阴君火在上，则阳明燥金在下，左边是太阳寒水，右边是少阳相火；太阴湿土在上，则太阳寒水在下，左边是厥阴风木，右边是阳明燥金；少阳相火在上，则厥阴风木在下，左边是少阴君火，右边是太阳寒水；阳明燥金在上，则少阴君火在下，左边是太阴湿土，右边是厥阴风木；太阳寒水在上，则太阴湿土在下，左边是少阳相火，右边是少阴君火。这就是所谓的“面南而命其位”（面向南方来确定方位）。所谓“面南命位”，是指在泉在下，方位在北面，人面向南方来定左右，那么东北方就是在泉的左间气，西北方就是在泉的右间气。
上面的气向右运行，从西南方下降；下面的气向左运行，从东北方上升，左右环绕一周天，剩余后再次会合。所以上下相遇，天地相邻，而变化有逆顺之分，由此产生。虽然同类相和、气化相生称为顺，异类相邻、气化相制称为逆；但是也有气虽属同类却致病的，是因为相火加临于君火之上，属于不当位所致。所以《六微旨大论》说：君位臣则顺，臣位君则逆，逆则病近且危害迅速，顺则病远且危害轻微，这里说的就是两种火（君火与相火）。这部分应当与前文《五运太少齐兼化图解》参看。
《六微旨大论》说：天道以六六之数分段，盛衰的原因是什么？回答说：上下有固定的位置，左右有纪纲秩序。所以少阳之右，由阳明主治；阳明之右，由太阳主治；太阳之右，由厥阴主治；厥阴之右，由少阴主治；少阴之右，由太阴主治；太阴之右，由少阳主治。这是讲述客气中阴阳的次序。
[Image: pt13a29.bmp - Diagram of Si Tian, Zai Quan, and Left/Right Intermittent Qi]
Song of Si Tian (Heavenly Ruler)
In Zi and Wu years, Shao Yin Jun Huo (Ministerial Fire of Shaoyin) governs; in Chou and Wei years, Tai Yin Shi Tu (Damp Earth of Taiyin) presides; in Yin and Shen years, Shao Yang Xiang Huo (Ministerial Fire of Shaoyang) is prosperous; in Mao and You years, Yang Ming Zao Jin (Dry Metal of Yangming) takes command; in Chen and Xu years, Tai Han Han Shui (Cold Water of Taiyang) borders; in Si and Hai years, Jue Yin Feng Mu (Wind Wood of Jueyin) presides. The first qi begins at the left intermittent position of the earth, counting from the positions opposite to Si Tian and Zai Quan.
Si Tian (Heavenly Ruler), Zai Quan (Earthly Ruler), and the four intermittent qis constitute the six steps of Ke Qi (Annual Variable Qi). That which governs the whole year is called Si Tian, located at the third step (San Zhi Qi). Opposite and below Si Tian is Zai Quan, located at the final step (Zhong Zhi Qi). To the left of Si Tian is the Left Intermittent Qi of Heaven, and to the right is the Right Intermittent Qi of Heaven. To the left of Zai Quan is the Left Intermittent Qi of Earth, and to the right is the Right Intermittent Qi of Earth. Each year's Ke Qi begins two steps before Si Tian, which is the Left Intermittent Qi of Earth, designated as the First Qi, proceeding sequentially through the Second and Third Qis, finally reaching the Sixth Qi of Zai Quan. Each qi governs one step. However, since Si Tian generally governs the first half of the year and Zai Quan the second half, it is also said that before mid-year, Heavenly Qi governs, and after mid-year, Earthly Qi governs.
The *Wu Yun Yun Da Lun* states: "Heaven and Earth are the upper and lower aspects of all things. Left and Right are the pathways of Yin and Yang." Wherever Jue Yin Wind Wood appears above, the left is Shao Yin Ministerial Fire, and the right is Tai Yang Cold Water; where Shao Yin Ministerial Fire appears, the left is Tai Yin Damp Earth, and the right is Jue Yin Wind Wood; where Tai Yin Damp Earth appears, the left is Shao Yang Ministerial Fire, and the right is Shao Yin Ministerial Fire; where Shao Yang Ministerial Fire appears, the left is Yang Ming Dry Metal, and the right is Tai Yin Damp Earth; where Yang Ming Dry Metal appears, the left is Tai Yang Cold Water, and the right is Shao Yang Ministerial Fire; where Tai Yang Cold Water appears, the left is Jue Yin Wind Wood, and the right is Yang Ming Dry Metal. This is referred to as "facing North to assign positions." To "face North and assign positions" means that Si Tian is above, positioned in the South. Facing North to determine left and right, the Southeast becomes the Right Intermittent Qi of Si Tian, and the Southwest becomes the Left Intermittent Qi of Si Tian.
It is further asked: What is meant by "below" (Zai Quan)? It is answered: If Jue Yin Wind Wood is above, then Shao Yang Ministerial Fire is below, with Yang Ming Dry Metal on the left and Tai Yin Damp Earth on the right; if Shao Yin Ministerial Fire is above, then Yang Ming Dry Metal is below, with Tai Yang Cold Water on the left and Shao Yang Ministerial Fire on the right; if Tai Yin Damp Earth is above, then Tai Yang Cold Water is below, with Jue Yin Wind Wood on the left and Yang Ming Dry Metal on the right; if Shao Yang Ministerial Fire is above, then Jue Yin Wind Wood is below, with Shao Yin Ministerial Fire on the left and Tai Yang Cold Water on the right; if Yang Ming Dry Metal is above, then Shao Yin Ministerial Fire is below, with Tai Yin Damp Earth on the left and Jue Yin Wind Wood on the right; if Tai Yang Cold Water is above, then Tai Yin Damp Earth is below, with Shao Yang Ministerial Fire on the left and Shao Yin Ministerial Fire on the right. This is referred to as "facing South to assign positions." To "face South and assign positions" means that Zai Quan is below, positioned in the North. Facing South to determine left and right, the Northeast becomes the Left Intermittent Qi of Zai Quan, and the Northwest becomes the Right Intermittent Qi of Zai Quan.
Qi above moves to the right, descending from the Southwest; Qi below moves to the left, ascending from the Northeast. They circle around the celestial sphere, completing a cycle and meeting again. Thus, when Upper and Lower meet, and Heaven and Earth approach each other, changes arise from these reversals and smooth flows. Although similar types harmonizing and generating Qi is called Smooth (Shun), dissimilar types approaching and restraining Qi is called Reverse (Ni). However, even among similar types, disease can occur because Ministerial Fire (Xiang Huo) approaches Sovereign Fire (Jun Huo), which is an improper position. Therefore, the *Liu Wei Zhi Da Lun* states: "When Sovereign occupies the position of Minister, it is Smooth; when Minister occupies the position of Sovereign, it is Reverse. Reverse leads to close disease and rapid harm; Smooth leads to distant disease and slight harm." This refers to the two Fires. This section should be studied in conjunction with the preceding diagram of "Five Movements, Too Little and Too Much, Equal and Combined Transformations."
The *Liu Wei Zhi Da Lun* states: "The Way of Heaven divides into six-six segments. What causes their waxing and waning?" It is answered: "There are fixed positions for Up and Down, and regulations for Left and Right." Therefore, to the right of Shao Yang, Yang Ming governs; to the right of Yang Ming, Tai Yang governs; to the right of Tai Yang, Jue Yin governs; to the right of Jue Yin, Shao Yin governs; to the right of Shao Yin, Tai Yin governs; to the right of Tai Yin, Shao Yang governs. This describes the sequence of Yin and Yang in Ke Qi.