If you loved Red Peony Gambler, try Big Time Gambling Boss
A bridge between a film you've already seen and one most people haven't. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Kōsaku Yamashita, and they both carry the foreign gem, outsider, raw mood tags, and they sit in Drama / Thriller territory. If that's the register that drew you to Red Peony Gambler, the second film will land in a comparable space — through a different lens.
foreign gemoutsiderraw
What Big Time Gambling Boss is
Ginza, nighttime. A ringing telephone. A yakuza godfather sickens, gambling rackets hang in the balance. Loyalists angle for succession. One stoic lieutenant declines to play politics. Enjoyed best alongside Fukasaku's contemporaneous Battles Without Honor and Humanity cycle.

