Saiyuki: v. 9 by Kazuya Minekura
Feeling down in the dumps about losing in the battle against God, Goku attempts to raise everyone's spirits with a game of Mahjung (sp?). He wins match after match until he scolds them all to snap out of it and shape up, leading to them playing a whole day straight of the game. Ready for another round, the gang approaches The God's Castle, where they run into a bit of trouble with talking toys, before finally reaching God. They kick major ass and succeed in beating him in the end. There is a flashback of when Sanzou was younger and had a run-in with a young God, who was a disciple to Ukoku Sanzou Houshi, a very powerful and wise monk. With the game over, the castle around them collapses, but they manage to escape. Amongst the ruins, Ugoku appears and picks up Gods (I think his name is actually Kouryuu) fallen monk hat and announces that he's ready for another game. Our heroes drive off into the distance, back to their usual bickering selves, but the story is far from over...