Once a student asked Suzuki Roshi, "Why do you have forty-minute zazen periods, when most Zen teachers in America have only thirty? My legs really hurt when I sit for forty minutes. Won't you consider having thirty-minute periods, at least in sesshin?"
Suzuki replied, "That's very interesting. I've been thinking that we should have fifty-minute periods." After a pregnant pause, he added, "But maybe we can compromise. Let's make it forty minutes."