This is a vintage Pocket Monsters Pokemon plastic rice bowl in white melamine or melmac. It is 4 1/4" wide and 1 7/8" deep. The bowl is decorated with 6 different pokemon, the only one I recognize is Pikachu. It is not dated, but the fact that they are called Pocket Monsters rather than Pokemon means that it dates to between 1996-1998. It is marked Taiwan on the base.
Pokemon Pocket Monsters Melamine Plastic Rice Bowl Vintage Made in Taiwan