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Several participants preparing for the tournament
The Grass Tournament is an annual Pokémon battle competition held in Johto. Competitors are allowed to use only one Pokémon, and only Grass-type Pokémon are permitted to enter. Each Pokémon Trainer fights for the prize, a trophy and a set of Leaf Stones.
In the anime
The 45th annual Grass Tournament was featured in The Grass Route. Ash Ketchum entered the tournament with his Bulbasaur, and Ephraim, a boy whom Ash met and told him about the tournament, entered with his Skiploom. Team Rocket also entered; James used his Victreebel, and Jessie, owning no Grass-type Pokémon, entered with Meowth, disguised as a Sunflora.
In the first round, Ephraim's Skiploom defeated James's Victreebel rather quickly. After winning in the first round, Ash's Bulbasaur was faring poorly against Meowth in the second round, who was doing surprisingly well, subduing Bulbasaur with its Scratch and Fury Swipes moves, until Bulbasaur's Razor Leaf shredded Meowth's costume. Meowth and Jessie were then disqualified, as Meowth is a Normal type.
Ultimately, Ash and Ephraim faced each other in the finals. Ash almost won the tournament, but Skiploom learned SolarBeam at the last moment and defeated Bulbasaur for the win.