On Twitter, Prop Anon spots an article by Ray Bradbury, "Zen and the Art of Writing," from the October 1958 issue of "Writer" magazine, available at the Internet Archive. In the article, Bradbury offers writing advice, and tells his readers to hunt up a copy of Zen in the Art of Archery by Eugen Herrigel. (Bradbury apparently gets the title slightly wrong.)
Prop wrote on Twitter that the Bradbury piece was "influential."
It certainly influenced Robert Shea. In the Science Fiction Review interview with Shea, which I referenced yesterday, Shea talks about how the article had a big influence on him. Shea also talks about his Zen practice, and his habitat of meditating every day. It's a very in-depth and interesting interview.