Doka (literally, poetry on the way) (道歌)
In contrast to tanka poetry as art, doka refers to tanka (31 syllables' poem) or waka (Japanese poem) that includes Buddhist teachings or that Zen monks composed to make study and spiritual enlightenment easier to understand.
The following poems are given as examples.
Depending on the state of mind, a body can decline even though the eyes, nose, mouth, hands and feet are healthy.'
No one could achieve anything if an instructor did not have his pupils observe and listen to it, show them how to do it, let them do it by themselves and praise them.'
Long before the famous aphorism by Isoroku YAMAMOTO, 'Show your subordinates how to do a thing, talk them into doing it...,' there was a doka composed with the same meaning.
When you make koicha (thick tea), be sure to use fairly hot water, dry the tea bowl before starting to make it, and stir the tea powder well into a paste; but it shouldn't be stirred so that the tea has bubbles or lumps.' (Doka by Rikyu)