Free Jansou Saikyou Densetsu One

Synopsis

Yorozu is a college student who feels like a total loser. He has no confidence, and he's always either worrying about messing up or agonizing about the things he's already messed up. After going to see his senpai Ken for help, he is thrown into the world of free mahjong parlors, where one plays against total strangers. Yorozu's never played free before, but luckily he has Ken, one of the best players around, to help him learn the ropes. And he's going to need all the help he can get, as the mahjong world is teeming with tough opponents... (Source: MyAnimeList)