The best mahjong manga for actually learning how to play mahjong. The main character is an online mahjong pro looking to break into the world of gambling. The story itself is relatively straightforward, and the art is charismatic and expressive. But the real star is the deep dive into riichi mahjong strategy, and what goes through the minds of players who play the game at a high level--the intricacies of reading one's opponents, navigating the vagaries of fortune, and walking a psychological tightrope to remain level-headed enough to make the right move at the right moment.
The narrative is fairly simplistic, as are the characters themselves. I'm not sure I'd recommend this to anyone who isn't already familiar with the rules of riichi mahjong. But if you are, you absolutely need to read this!