Simplify the following text for a Grade 6 native English-speaking person.
Original: On June 30 , 2009 , Yamamoto joined the ECW brand and debuted under the ring name , Yoshi Tatsu which he joined because of their new superstar initiative .
Simplified: On June 30 , 2009 , Yamamoto joined the ECW brand under the ring name Yoshi Tatsu .