Akagi is a manga about the game of Mahjong by Nobuyuki Fukumoto published for the first time in 1992. It has been adapted into anime in 2005.
Summary of the anime Akagi:
Akagi is a thirteen year-old teenager who loves the rush of the adrenaline and thus bets a lot, often risking his own life. Trying to escape the police, he will find himself playing and winning at mahjong, a game he has never played before. He will quickly climb the ladder of the mahjong underworld and encounter better players every time. His will, unbent, will lead him to the highest and most dangerous enemies he has ever played with. There is no turning back for Akagi.
My opinion on the anime Akagi:
I have to admit that mahjong is a bit complicated to me, but the entire anime stands on suspense, handled with an expert hand all along. Besides, you will get plenty of explanation about mahjong during the anime. Akagi is pretty different from most animes so I cannot tell if you are going to like or not. Some might get bored quickly, arguing about a weak script, not credible a bit, while others will not be able to stop watching until the very end. You may be bummed by the strange chara-design but that honestly is not something you should be focusing on. Besides the suspense, it is a bit hard to tell where Akagi manages to score points but it definitely does. Maybe it is the fact that we are left unaware of his deepest motivations. We mostly see him as a bad guy, but we like to think that he is actually one of the good ones. I recommend you watch the first episode at the very least and make an opinion for yourself.