every time you get the slightest bit stressed, you're gonna hear that whispering sound effect in your head. "zawa zawa zawa"
But yeah. It's on my GOAT anime list. I thought I was going to be put off by the artwork, but the story is so intense that you barely notice. You'll never look at Rock/Paper/Scissors the same way again.
If you're bored enough, you should check out the other two anime in the writer's "Gambling" trilogy:
Akagi, which is about Mah-Jong and the criminal underworld. No, you don't have to know how to play to watch it. Akagi is one of anime's great villain protagonists. A cold blooded monster that preys on nothing but other villains.
And
One Outs, which is just as much of a mindfukk as Akagi and Kaiji... but is about Baseball. The lead character has an 88 mph fastball and agrees to a contract where he gets 5 million yen for every out he pitches, but loses 50 million for every point he gives up.
Also of note is the fact that the same voice actor is used for all three lead characters. But their personalities and levels of ruthlessness is so different that you'd swear it's three totally different people.