Source: Kusumoto Bunyū’s (久須本⽂雄) 1982 book Zengo Nyūmon (禅語⼊⾨, An Introduction to Zen Words and Phrases, Tokyo: Daihōrin-kaku Co. Ltd.
URL (English translation by Michael D. Ruymar, but this translation still provides lots of the original Chinese): https://terebess.hu/zen/Zengo.pdf
Record of Mysterious Wonders, aka, Signs from the Unseen Realm
冥 míng dark, the underworld (not in hsk)
祥 xiáng auspicious, propitious (hsk6)
記 jì record (hsk3)
出 = come out, leave
門 = gate
逢 = meet
釋迦 = Shakya, the historical Buddha
知音 lit: know sound; meaning: one who listens attentively, bosom friend, a friend who understands you
何必 lit: why certainly; meaning: why?
鼓唇牙 lit: drum, lip, teeth; meaning: nonsense sounds
my “translation”: No words are needed between these two friends
Light and dark oppose one another like the front and back foot in walking. (English translation)
Most of the characters in this line from the Sandokai are very common Chinese words. Six out of the ten characters are part of the most basic level of Chinese proficiency for those learning it as a foreign level (HSK level 1). Only two of the characters are relatively “advanced”, one is HSK level 4 (各), and other is level 5 (暗). But in fact both of these characters are easy to recognize and have fairly simple meanings.