+1 to Akagi, IIRC it's by the same guy as Kaiji, and it's very good. It focuses almost entirely on mahjong though, and goes fairly in-depth, so my advice would be to quickly read up on the rules of Japanese riichi mahjong before watching. The subtitles have lots of notes, and it's fairly easy to pick up details from watching, so you don't need to be an expert to understand what's going on; but a basic familiarity helps.
If you like Akagi, then Legendary Gambler Tetsuya is very similar, so is worth trying. You might also want to consider Hikaru no Go; in some ways the anime itself isn't particularly deep or intellectual, but it spends most of the time focusing on Go matches in great depth, which is a very thoughtful, strategic game with a lot of depth to it; so you might like it (again, might be worth reading up on the rules of Go first - but they're so simple, it's probably not really necessary. Surprisingly simple, in fact, when you consider how deep a game it is).