Biographical?

not autobiographical, although i do see similarities between fukasaku's take on the war, and hirono's take on the yakuza war.. but it is based on the yakuza papers-a serialized newspaper autobiography by a yakuza member written in jail.

Hirono got angry at reading a article on a magazine in a jail, which justified his archenemy to do something among Yakuza battle. Then Hirono started writing a story which he found a true story in ordert to build up a counterargument. Apart from its context is true or not, basically Hirono called it "autobiograhy".

It was based on a newspaper series written by a former yakuza about his life in the rise of at least two of the major the post-war yazuka gangs,so yeah, it was based on a true story. (All that info is in the booklet that comes with the boxed set---it's very well-written and informative.) I like the fact that it's a very harsh, realistic, unglamorized view of the yakuza life,showing them not as honorable heroes, but as straight-up psycho thugs. It was considered a ground breaker and game-changer in terms of yakuza depictions onscreen for its time, and very popular (that's why there were 5 films in the series.) For other films in that vein, check out Graveyard of Honor & Yakuza Graveyard (which I like the best of the two.)