I'm probably giving this book a higher rating than it deserves, because I'm remembering it from when I read it as a teenager. It's a cheesy, blood-splattered "Oriental" (I deliberately use the pejorative term) novel of dubious verisimilitude with steamy but pointless sex scenes. It was written when the ninja craze was just beginning in the U.S. In short, it's mindless pulp entertainment with not much of a plot, but I still have fond memories of it.