Board Thread:General Discussion/@comment-27172747-20151107131413/@comment-3423279-20160308024330

Zanka no Tachi isn't safe for others if you aren't hit by its attacks.

Royd said that if it wasn't for his Blut Vene then he would of burnt to ashes just being near Yamamoto, and even from far away it still immediately evaporated all the moisture in Seireitei just by being activated, and melted Toshiro's Bankai which is considered the strongest Ice Type.

I personally think that you either have to hold an outrageous amount of reiatsu on the level of either Dangai Ichigo or Hogyoku Aizen, or be at least Captain Class with an exceptionally powerful defensive technique like Heirro or Blut Vene.

Shunsui's Bankai is definitely powerful, and can be used to injure foes that can't otherwise be injured such as the Intangible Mega Ultra Chicken Lille to a great degree but it doesn't seem to have a nearly unbeatable defense like Yamamoto's sun shield, merely a deterrence from attacking him as the wound might be reflected on you as well.

In addition Shunsui made a point to think that he couldn't use it around his allies as his Bankai will affect anyone within it's area of influence, so it isn't exactly a safe Bankai to pull out when surrounded by your allies.