Simplify the following text for a Grade 6 native English-speaking person.
Original: Kazuma Watanabe ( æ é å ç Watanabe Kazuma ) born 10 August 1986 is a Japanese footballer who plays for Yokohama F. Marinos .
Simplified: Kazuma Watanabe ( born 10 August , 1986 ) is a Japanese football player . He plays for Yokohama F. Marinos and Japan national team .