Weapons That Do Not Sell On AH

On most pages of equippable items there's a line that says something like "Root / Weapons / Daggers", which indicates what sort of weapon this particular item belongs to. For weapons that don't sell on the Auction House, such as all the new ZNM ones (Shusui, Foolkiller, etc), it doesn't list what sort of weapon it is. I spent ten minutes trying to find out what Nanatsusayanotachi was and ended up getting the answer from Wiki.

I know it's not a serious issue since this applies to perhaps a few dozen items max, but maybe the sort of weapon or item they are somewhere on their pages would help to clear any confusion?