Recently I've been reading it. Here's the opening :
My name is Miyamoto Musashi. I have killed over sixty men in fights and duels. When I was sixty years of age I looked back on my life and in a flash of wisdom, realized that all my victories were based on either great luck, an innate ability, or perhaps the fact that the methods of other schools were inadequate.
Make no mistake about it: this is a book about killing people. Transposing this to business practice is a way big leap in interpretation. A couple of times Musashi does say to apply his principles to all aspects of one's life, but he's talking about a warrior being consistant as a warrior. I think finding business ideas here is really an attempt to acquire the glamour of Musashi by proxy.
Incidentally, a few years ago they ran the NHK Taiga drama Musashi on TV. Fifty-three two hour episodes. It was very entertaining.