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Remembered about this post just in the nick of time.
Title: RロックンRロールRリッキー, Rock n' Roll Ricky, RRR
Author: Watanabe Jun
Genre: Seinen, Comedy, Sports
Serialized in: Kodansha Young Magazine
Total Volume Count: 10
Series Summary from MangaUpdates:
Rikitaro is a musician whose dream is to become a rock star just like Jimi Hendrix or Jim Morrison, but at the age of 27 that dream is fading away rapidly. Ooishi is a 3 time world boxing champion who recently retired and is now in the entertainment world, shooting a boxing reality show.Kenn's Comment: Started reading this one a few weeks ago, and loving every bit of it. I'm normally not someone who reads manga about boxing, let alone any sports series, but this one is really good. The beginning is a tad on the heavier side, but it quickly starts to lighten up a bit, so don't let the beginning bring you down.
These two unlikeliest of people cross paths one day, but both of them think nothing of it until weeks later. Rikitaro is given one last shot by a record label to sign a deal but before that, they need him to get into better shape so that he is easier to sell. He stumbles upon a boxing gym which also happens to be the same gym Ooishi is filming his show.
As fate’s wheels start to turn, neither man realizes that they will work together to train the best boxer ever, even better than Ooishi himself.
The characters, or at least the main cast, are fairly well fleshed out from the extent that I've read. Main cast being the handful of characters that really have a backstory to them. I'm sure other characters get their turn in the limelight, some more likely than others. Anywho, it's a great read for anyone interested, and while boxing is certainly one of the main elements in the series, most of the series takes place out of the ring.