The Chinese term Huihu, an important concept within the Caodong sect of Chan, first appeared in Shitou Xigian’s text, Cantongqi. This text, known in Japanese as the Sandokai, is an indispensable part of the canon of Soto Zen, and is recited in Soto temples daily. Huihu—a central concept within the Cantongqi—means “transposition,” or “interaction.” It refers to the phenomenal interchange between polar entities, like winter emerging into spring or vice versa, or vexations transformed into liberation or vice versa. Hui means “return” and hu means “mutually,” so a literal translation of the concept would be “mutual return to the state (of the other).”

What huihu really offers is an expansive view of the impermanence of everything. Huihu synthesizes this fundamental Buddhist tenet with the Taoist principle of the interplay of polar opposites in nature, whose philosophical roots can be traced to the I Ching. The Caodong sect’s use of huihu, as taught by Chan masters still to this day, is most interesting when it is used to describe the experiences one encounters in practicing meditation. As one proceeds along the various stages toward ultimate liberation or complete enlightenment, there is an ongoing interplay (huihu) between vexations and wisdom (or liberation), rather than a simplistic removal of vexations. In describing the transposition (huihu) between vexation and liberation, the Cantongqi says,

    In the midst of brightness, there is darkness
    Do not take darkness as darkness.
    In the midst of darkness, there is brightness
    Do not take brightness as brightness.
    Brightness and darkness correspond, like one step following another.

Brightness here refers to wisdom, liberation, and enlightenment, whereas darkness refers to vexation, bondage, and confusion. Every practitioner will sometimes experience “brightness” and at other times “darkness,” as they continue along the path of meditation. What these verses are trying to tell us is that brightness and darkness are huihu. They will mutually transpose, so it is not sensible or helpful to be discouraged by the darkness one encounters or to fixate on the brightness attained or longed for. Vexations, once let go and removed within practice, can unexpectedly lead straight to enlightening experiences. Enlightening experience, no matter how blissful, will soon die out and cover you up with clouds of vexations if you try to grasp it. If you feel wisdom, remember that vexation—its polar opposite—is hiding behind its back.

Brightness and darkness will always alternate along the path of practice, until you go beyond the realm of dichotomy. At that point, one encounters neither vexations nor wisdom, which is what we would call “no huihu.” There is no more transposition encountered in the practice. The great Caodong master Hongzhi, who first articulated the method of silent illumination, said, “When the seeing [of self-nature] is complete, huihu rests.” That is cessation, ultimate liberation, beyond the most blissful event we could hope to attain.

WING SHING CHAN has studied closely with Master Sheng Yen and is a freelance writer on Chan Buddhism. He lives in Hong Kong.