The head of a major construction firm wants some one killed; price is no object. He contacts a hitman's (and hitwoman's) club, saying he wants the best. They argue over who that individual is. When they set up a challenge to determine the answer, outsider Yûsuke Kawazu inadvertently wins and gets the contract. However, he's distracted by having fallen in love with Shima Iwashita. Guess who the target is!
In between there are the usual eccentric hitmen (and hitwoman), bright colors and songs. Yes, this is Crime Musical, with ballads like "You're an Uptown Hitwoman and I'm a Downtown Hitman". At first it seems like an eccentric and frequently foolish burlesque of a popular form. However, I believe the film makers had a serious point.
This was the early 1960s, and young film makers were anti-industrial, anti-pollution, anti-corruption, all the hallmarks of the political/social/economic system that was propelling Japan from a post-War recovery into prosperity: in a word, Communist. Young film makers were decrying stodgy film makers like Kurosawa, even as he put subtext into YOJIMBO, and clear text into other movies. The corrupt businessmen who kill off inconvenient reporters, the corrupt editors who take money to kill embarrassing stories, while the audiences complacently watch meaningless musicals with songs about the glories of death-dealing... these were the targets of this satire.
The question then becomes not was this a meaningless artifact of pop culture, but how well it succeeded. Judging by the reviews I've seen, no one noticed. Everyone seems to have thought it was a silly thing. So I'd say it didn't have any effect and while we can enjoy the artistry, the serious message, the bones of the movie, the subtext, was wasted.
