I have a lot of Japanese ceramics (and teaware) vendors saved. I will share a few. These ones are more on the accessible side and I think they suit the tastes of this forum.
Inbeya - All bizenyaki. Site is in English.
https://inbeya.com/englishindex.html
Bizenyaki kibido - all bizenyaki. All in english. This site is linked on the wikipedia page for Bizen.
https://www.bizenyakikibido.com/index.p ... ry&path=61
Sou - Everything, literally everything. They have an ebay but this is their main site. In English.
https://www.net-qp.com/en/
Shoindo - Teaware and other things. Japanese website only. I include them because they will ship abroad, also this is a famous store. It is on one of the famous roads in Kyoto. I actually visited Kyoto and wandered in by accident and was really confused why all the stuff looked so familiar!
https://www.rakuten.ne.jp/gold/shoindo/
Tablin store - Very helpful and friendly. Sells teaware and knives and other things.
https://www.tablinstore.info/
Japan Pottery Net - As the website name says, they sell japanese pottery. I think it looks slightly marked up but nothing crazy.
https://www.japanpotterynet.com/en/
Naganawa - website in Japanese only but they will ship to USA if you email them. Notable for all the iga yaki, bizen yaki, and other earthy styles.
http://www.naganawa.jp/
Enjoy.