Unique nakago jiri

[Fuuten]

Good evening,

 

While browsing the auctions on Aoi I noticed the following ken which to me stands out because of its unique nakago jiri. I checked a couple of search results on Google and the forum but couldn't place it specifically or find another example like it. 

 

I would describe it as a rounded variation on a stupa but honestly don't recall having seen anything exactly like it. Could it be something unique to the Yamato tradition? If there's a name for it I'd love to learn it. Thank you.

 

Auction: https://www.aoijapan.com/kenmumei-monju/

 

[WillFalstaff]

First time I've seen this, in my limited experience. It makes sense, though, artistically. Each side of the ken is a reflection of the other.