I just finished the 47 Samauri.
Not a bad book but of course it requires you to suspend disblief to make it work. Instead of buying the hardback in a years it will be a paperback at 1/3rd the price.
As for a good movie script, perhaps, but I think it's already been done by Sidney Pollack.
Find the 1974 "The Yakuza" and see how great it is, staring Robert Mitchum and Ken Takakura.
bushi no te isshinryu
offering free instruction for 30 years