Japanese Karatsu chawan

Pretty sure it's a Japanese Karatsu chawan, but looking to find the name of the potter from the signature.

Thanks!

This incised signature is relatively unusual and so it could be compared to other work by the same potter and identified but I am not familiar with it.

Is there anything other than the appearance that makes you "feel pretty sure" that it's Karatsu yaki?

Here is a good Japanese pottery reference and buy site: https://chano-yu.com/

I purchased it on auctions.yahoo.co.jp and it was listed as Karatsu-yaki, presumably from the box. I neglected to post a picture of the box! Sorry about that. Here it is.

Obviously, the box makes a considerable difference and much easier to identify. I wasn't doubting that it looked like Karatsu yaki but because of where you lived the thought crossed my mind that it might have been made nearer to you and not in Japan.

The way that I attempt to find the name of the potter is to search eBay etc. for Karatsu chawan and hope something comes up. It sometimes works but it can be time consuming.

The fact that the potter wasn't identified when you bought it would suggest that it isn't a well known artist.