Regarding yielding the attack:<br/><br/>In the prologue fights, the NPCs are able to yield indefinitely, since they would be the winner by default if nobody attacked.<br/><br/>In the tournament, it will not be allowed for two yields to occur in a row.  If one fighter yields the attack to the other, the other must attack at least once before yielding the attack back.  If anyone's familiar with Go, just think about the ko rule.