I have had a fairly long connection with American Zen Buddhism. Roughly 45 years, including Zen practice, being on many boards of directors and knowing a large number of people in that population. I've also visited some of the major temples in Japan.
I published two books by Zen abbotts. One of them is a book of modern, up-to-date koans.
A koan is a short riddle that comes from the Rinzai tradition of Zen Buddhism. The teacher in that particular line of teaching uses the koan as a way to help the practicing Zen student to clear his mind. It is a puzzle that does not have an single answer. The puzzle might be: ‘How many stars are there?’ ‘ Where do clouds go?’ ‘ When I make this sound how do you know the universe?’ The student is to meditate on these puzzles.
When the answer indicates that the student is no longer, trying to solve the puzzle and is focused on the immediate world, then the koan has done its job. The student might reply to any one of those puzzles with: “Can I pour you some tea?” Or the student might take a stick and pound it on the ground. The student who understands the koan will show a response in the immediacy of time and space.
While talking to a recent Buddhist friend about our pasts, since we have not seen each other for nearly 4.5 decades I realized that I didn't need to know what she was going to do in the future. The koan suggested by this meeting would be:’What are you going to do?’ The answer was simply seeing her after 45 years because she embodied everything she has been and will be.