OOYAMA is an artist for the Pokémon TCG. He most famously worked on the Super Famicom game MOTHER2 as the art director.
He was part of the team that initially designed the Pokémon Trading Card Game. In recent years, he has been illustrating the Pokémon Old Maid game. He is also developing new games under his personal brand, OOYAMA GAME. Dr. OOYAMA, a character that appears on some Japanese cards in the Pokémon TCG, was based on him.
OOYAMA was one of the Illustrator Judges for the 2024 TCG Illustration Contest and they were quoted saying: "I was chosen as a judge for this contest, but as an illustrator myself, I'm not quite sure how I'm supposed to go about judging other people's illustrations! (Laughs)"