Board Thread:Questions and Answers/@comment-115.178.236.175-20161005101320/@comment-3444885-20161005142709

Nothing can instantly break a sword. The worst that can be done is bring him down to 1HP, severely injure him (Red), and then push him to the back where he can no longer be hit (all at once). Basically, if he's not in the red when you start the battle, there is absolutely no need to worry.

As for the swords more at risk to this... Yari damage I think is fixed to 7-9HP. For tantous who only have like 30~HP, this means their health can be brought down 1/3 in one hit. For the big boys it's not as big of a deal, but it's definitely dangerous for tantous (or anyone with HP lower than 40).