Manga Title: One Outs
Genres: Psychological, Seinen, Sports
175 chapters in 20 volumes (published 1998-2009)
Extra: Although this is a baseball manga, the main focus of it is actually gambling. You really don't have to be interested in sports to get hooked on the plot. It's often compared to Akagi, Kaiji and Death Note because there are a lot of mind games and Keikaku doori moments. Our pratagonist is a gambling demon who is set to make a very weak baseball team win the championship. He uses the psychology and physical pressure of professional athletes as well as sports corruption and politics to achieve his goal.
Personally, I feel like the manga is a little underappreciated. In fact, it's not even fully scanalated. Some chapters were skipped and you have to watch them in the anime adaptation (chapters 32 - 54 = episodes 9-16, chapters 62 - 82 = episodes 18 - 25). So I would recommend to just watch the 25 episode TV show (made by Madhouse) and continue reading the manga from chapter 82. There are a couple of minor differences but otherwise the anime is as close to the source material as it can get (and the soundtrack is pretty well done too).