"That's why, in my place, I'm always telling everyone, 'Abide in the unborn Buddha mind and nothing else!' Other than that, I'm not setting up any special rules and making them practice. All the same, since everyone got together and decided to practice for 12 sticks of incense every day, I told them, "Go ahead, do whatever you like'; so I'm letting them practice every day for a period of 12 sticks of incense. But the Unborn Buddha Mind isn't a matter of 12 sticks of incense! When you abide in the Buddha Mind and don't become deluded, then, without looking for enlightenment outside, you'll just sit in the Buddha Mind, just stand in the Buddha Mind, just sleep in the Buddha Mind, just get up in the Buddha Mind, so that in all of your ordinary activities you function as a living Buddha. There's really nothing to it.
"As for zazen, since 'za' (sitting) is the Buddha Mind's sitting at ease, while 'zen' is another name for Buddha Mind, the Buddha Mind's sitting at ease is what's meant by zazen. So when you're abiding in the Unborn, all the time is zazen; zazen isn't just the time when you're practicing formal meditation. Even when you're sitting in meditation, if there's something you've got to do, it's quite all right to get up and leave. So in my group, everyone is free to do as he likes. Just always abide at ease in the Buddha Mind. You can't simlply remain sitting from morning til night, so walking meditation for one period; and you can't just keep on your feet, either, so sit down and meditate for one period. You can't very well do nothing but sleep, so you get up; and you can't just keep on talking, so I let you practice meditation. But this has nothing to do with rules."
-Bankei Kotaku (from Bankei Zen, p.58-9; tr. Peter Haskell.)
Note: Bankei's practice instructions were simple: recognize the "marvelously illuminating" Unborn Buddha Mind, your own present awareness, which is always functioning, and abide in it. He would often direct people to notice how the mind continuously and spontaneously illuminates and presents objects without any personal effort, and tell people just to abide in that, without trading their "Buddha Mind" for thoughts and becoming a "hell-dweller, hungry ghost, animal or other deluded being". Do just that, said Bankei, and you abide as the living Buddha you already are.