The haiku I'm looking for is probably of an anonymous author. I got a hint on a Japanese message board that it's maybe Musashi's one and I should find it in Eiji Yoshikawa's famous novel, but it's not there. I have only the Russian translation of the haiku. In English it's like this:
Chain wrapped around a [tree] trunk and immediately
the noblest blade has struck [a blow]
The master demonstrated his skills
Does anyone remember something like that or give me another hint?