With the news today of Leonard Cohen (z"l), I was surprised to find out he was ordained as a Zen monk as well as seeing Judaism as his religion. I read:
He’s carried his Jewish faith with him throughout his life, regularly observing the Sabbath.3 Even after he started studying Zen Buddhism he said,
I’m not looking for a new religion. I’m quite happy with the old one, with Judaism.4
And Cohen’s study of Zen wasn’t just a weekend project. He lived at a Buddhist monastery for five years5 and became a fully ordained monk in 1996.6
About reconciling Buddhism and Judaism, Cohen said,
Well, for one thing, in the tradition of Zen that I’ve practiced, there is no prayerful worship and there is no affirmation of a deity. So theologically there is no challenge to any Jewish belief.7
Personally I am of the view that we have to decide for ourselves what G!d requires of us, but I was curious what the halachic position would be on this situation.