The Authenticity of Genius
At the Kawada group's headquarters, the fake Akagi (Yukio Hirayama) and the genuine Akagi face off to demonstrate their skills. Akagi insults the impersonator, because of his reliance on his mathematical skills and excellent memory, and shows him just how frightful his talents are. Following this he then returns to his workplace to find his senpais swindling Osamu in a game of Mahjong.
Aired 30/11/2005EP 9 - The Authenticity of Genius

Akagi
While mahjong is a game that is often played with family and friends, it is also a game that is played in the darkest corners of society. Nangou is a compulsive gambler who has accumulated a debt of over three million yen. In a last-ditch attempt to clear his record, he decides to wager his life on a game of mahjong with the mafia. Unfortunately, as the game progresses, Nangou only moves further from the prize and closer to death.
When all hope seems lost, the game parlor is suddenly intruded upon by Shigeru Akagi, a young boy on the run from the police. Desperate to turn the game around, Nangou hands the game over to Akagi after teaching him a few of the rules. The mafia can only smirk as Akagi sits down to play. However, they soon come to learn that Akagi is a natural-born gambler. An imposing figure who does not fear death. One who is destined to become a legend.
(Source: MAL Rewrite)