Several times now, I’ve seen red kanji numbers on vintage & antique Japanese earthenwares. They are usually located on the unglazed rim and their numbers match. Still not sure what they mean, but I think the numbers have to do with studio, kiln, factory, or pavillion number.

I’m not sure why Chinese porcelains with this type of markings are being scavenged like crazy in Asia. I do agree that the porcelain which has this type of stamps are of high quality. The ceramics are 20th century, but antique dealers in Asia would say that people from Mainland China buy up these ceramics in single swoops. Now, these antique dealers did not keep any for themselves (which they regret). My friends and I can confirm that these type of markings are getting harder to find now (even if they are 20th century pieces). And if one does find one, it would cost three or four times more than what it cost once.

A strong blue tone. Some signs that the pigment was not mixed well enough and thereby, the slight breakup of colors and pits — this may not be a bad thing and could possibly be used as a hint for authenticity. Modern mixing technology (mass production) may be too refined to have this type of mark.