Birth of the Strongest Combination in Shinjuku
Tetsuya turned down Boshu's offer to become partners. He was confronted by a pair of twins, both professional gamblers. Tetsuya was able to decipher the gestures used by the twins to signal each other… But he was in a tough spot because he couldn't figure out how they were swapping tiles with each other. Boshu saw through their act and told Tetsuya that they're using their rings to hide the tiles. Boshu and Tetsuya decide to team up, and proceeded to crush their opponents with a stacking technique called "Double Deuce Tenho!" On that day, Japan saw the birth of Shinjuku's number one team.
Aired 28/10/2000EP 4 - Birth of the Strongest Combination in Shinjuku

Gambler Densetsu Tetsuya
In the year 1947, the people of Shinjuku are down on their luck. With little money to buy food or necessities, some resort to gambling in order to survive. Traveling Tetsuya chooses to spend his time at Mahjong parlors where he is wiping the floor clean with his adversaries. However, when Tetsuya meets the intensely skilled Boushu-san, he realizes that his skills are still lacking.
(Source: Anime News Network)