The Yagyu Clan has a strict code of conduct that is expected to be followed out to the letter.  Any violation of the code may result in banishment from the clan pending further inquiry. However generous rewards are also to be handed out to those whose conduct shows merit.

 No member of the Yagyu clan is to engage in any form of verbal confrontation. This means on the field of battle as well as in the channels or ANY forum

All members of the Yagyu clan will bear the name Yagyu as a prefix for the acct. A name will be chosen for you by the high council. All members will be identified with the Yagyu- prefix on the acct. Your characters will be a name of your own choosing with or without the Yagyu- prefix

It's neither condoned no endorsed. It's at your own discretion. However, in-clan dueling, dueling with allies or hostiling allies are not allowed. Ironman being the ONLY exception to this rule.