古称乙癸同源，肝肾同治，其说维何？盖火分君相，君火居乎上而主静，相火处乎下而主动。君火唯一，心
主是也。相火有二，乃肾乃肝。肾应北方壬癸，于卦为坎，于象为龙，龙潜海底，龙起而火随之。肝应东方甲乙，
于卦为震，于象为雷，雷藏泽中，雷起而火随之。泽也海也，无非水也，无非下也，故曰乙癸同源。东方者，天
地之春也，勾萌甲拆，气满乾坤。在人为怒，怒则气上而居七情之升。在天为风，风则气鼓而为百病之长。怒而
补之，将逆而郁结。风而补之，将暴而摧折矣。北方者，天地之冬也，草木黄落、六宇萧条。在人为恐，恐则气
下而居七情之降。在天为寒，寒则气惨而应万象之衰。恐而泄之，将悚而颠扑。寒而泻之，将敛而战栗矣。所谓
东方之木，非虚勿补，补肾即所以补肝。北方之水无实毋泻，泻肝乃所以泻肾，中有至理也，
故曰肝肾同治。虽然木既常实耳，水既常虚耳，又言补肝泻肾者何哉？盖邪不可亢，亢则害正，泻之犹补之也。
正宜长固，固则御邪，补之犹泻之也。若夫血不足者濡之，水之属也，滋水之源，木赖以荣。气有余者泄之，木
之属也，伐木之干，水用而充，则又是肝肾同治矣。少火生气，气有余便火。壮火食气，气不足便是寒。泻木所
以抑气，补水所以制火，气即火，火即气，则又是乙癸同源矣。是为说。
The ancients stated that "Yi and Gui share the same source, and the Liver and Kidney are treated together." What is the basis for this theory? It is because Fire is divided into Ministerial Fire (Jun Huo) and Ministerial Fire (Xiang Huo). Ministerial Fire resides in the upper part and governs stillness, while Ministerial Fire resides in the lower part and governs movement. There is only one Ministerial Fire, which is the Heart Master (Zang Zhu). There are two Ministerial Fires, namely the Kidney and the Liver. The Kidney corresponds to Ren and Gui of the North, belongs to the Kan trigram in the Eight Trigrams, and symbolizes the Dragon in imagery. When the Dragon hides at the bottom of the sea, its rising brings fire with it. The Liver corresponds to Jia and Yi of the East, belongs to the Zhen trigram, and symbolizes Thunder in imagery. When Thunder hides in the marsh, its rising brings fire with it. Marshes and seas are nothing but water, and nothing but below; thus, it is said that Yi and Gui share the same source. The East represents Spring in Heaven and Earth, where buds sprout and shells split, and Qi fills the universe. In humans, it manifests as Anger (Nu); anger causes Qi to ascend, belonging to the ascending category among the Seven Emotions. In nature, it manifests as Wind (Feng); wind agitates Qi and becomes the chief of all diseases. Tonifying anger will cause Qi to rebel and stagnate. Tonifying wind will cause violent destruction. The North represents Winter in Heaven and Earth, where grass and trees wither and fall, and the universe is desolate. In humans, it manifests as Fear (Kong); fear causes Qi to descend, belonging to the descending category among the Seven Emotions. In nature, it manifests as Cold (Han); cold makes Qi bleak and corresponds to the decline of all phenomena. Draining fear will cause fright and falling. Purging cold will cause contraction and shivering. Therefore, regarding the Wood of the East, do not tonify if there is no deficiency; tonifying the Kidney is the method to tonify the Liver. Regarding the Water of the North, do not drain if there is no excess; draining the Liver is the method to drain the Kidney. This contains profound principles, hence it is said that the Liver and Kidney are treated together. Although Wood is often excessive and Water is often deficient, why speak of tonifying the Liver and draining the Kidney? Generally, pathogenic factors should not be allowed to become hyperactive; hyperactivity harms righteous Qi, so draining them is akin to tonifying. Righteous Qi should be firmly consolidated; consolidation resists pathogens, so tonifying is akin to draining. As for insufficiency of Blood, moisten it; this belongs to the category of Water. Nourishing the source of Water allows Wood to flourish. For excess of Qi, drain it; this belongs to the category of Wood. Pruning the trunk of Wood allows Water to fill up; this is again the treatment of the Liver and Kidney together. Mild Fire generates Qi; excess Qi transforms into Fire. Vigorous Fire consumes Qi; insufficiency of Qi results in Cold. Draining Liver Wood suppresses Qi; tonifying Kidney Water controls Fire. Since Qi is Fire and Fire is Qi, this illustrates that Yi and Gui share the same source. This is the explanation.