You're going to love it :) I damn near never guarantee someone is going to love a book, but I figure almost anyone here would. Everyone, literally everyone I'd recommended or gifted a copy of Musashi too is crazy about the book.
At the risk of getting way ahead of myself, Taiko by the same author is quite good too, but larger in scope - more characters, more history, a bit more work but still a good story. If you really like Japan or Yoshikawa's writing style, check that out afterwards. But for now, you're in good hands with Musashi. Feel free to drop me an email if you've got thoughts as you're reading, my email is in my profile.