Yu-Gi-Oh Vol 1

Yu-Gi-Oh Vol 1 by Kazuki Takahashi. A Shonen manga rated Teen, published in English by Viz Media in 2003.

Shy high schooler Yugi Mutou solves the ancient Millennium Puzzle and awakens a mysterious second spirit inside himself, a master of games. Whenever Yugi or his friends are threatened, this other self steps forward to challenge their enemies to high-stakes Shadow Games.