The main character is the violent drummer Shoichi, and the story charts his rise to fame and a few people around him. The story makes much of his torrential bad temper and outbursts of hitting people yet, when fame does arrive, it contains two contradictions. First, although he achieves public attention in a drumming contest, the points at which the crowd swings his way is when he is forced to stop frantically banging at the drums and start singing.
And what a voice ! Shoichi is played by a real-life very popular singer whose sweet crooning reminds of a young Bing Crosby. This leads to contradiction number two, which is that his songs are gentle. Doesn't fit at all with the character.
My resident translator assures me that, in the late 50s when this film was first released, the lifestyle portrayed by this bunch of fairly dissolute wannabe American-style jazzmen would have been viewed with envy by Japanese audiences.
I can't tell whether the director was copying those rock'n'roll teen flicks which were so common then, or if he was trying to fit in some serious drama as well. I think the result is an off combo of the two.
Incidentally, what is continually referred to as jazz in this film would probably puzzle any western fan. There's lot of music in this film, covering pop, light rock, swing, ballads, modern classical .... in fact, everything except jazz !
The result is patchy. Not dull enough to entirely dismiss, not consistent enough to be all-the-way entertaining, but far from great. Best I can say is it's an interesting period piece about mixing of cultures.