IJN Sakawa

Bushido 4 (Whenever this creature blocks or becomes blocked, it gets +4/+4 until end of turn.)

When IJN Sakawa attacks, if your opponent has one or more creatures able to block, choose one of them
to block IJN Sakawa. Your opponent can not choose additional creatures to block IJN Sakawa.

IJN Sakawa can not attack if your opponent has no creatures