Why are so many dated around 1900?

Of the 283 listings, 173 sit in the 1900s. That reflects dealers entering a round "1900" for late Meiji Japanese plates rather than pinning down a year. Everything else is thinner: forty listings say only "19th Century", ten the 1890s, eleven the 1880s, and a handful reach the 18th century.

Are these Japanese or English?

Japanese porcelain accounts for roughly three-quarters of what has been listed on Sellingantiques, with "Japanese" in 207 of 283 titles. English ironstone and bone china plates in Imari or Japan pattern make up under a tenth. Chinese Imari is rarer again, named in eight titles.

What sizes do they come in?

Nine inches is a typical stated size for a plate and twelve inches for a charger. The largest with a size given is a Japanese plate of 55cm diameter, dated to around 1890. "Large" appears in forty-four titles.

Do they sell as singles or sets?

Singles are the usual unit and fill the lower and middle of the range. About a third of listings describe more than one plate. "Pair" turns up in sixty titles, and groups run to sets of three, four, five, six, ten, twelve, a set of seventeen dessert plates and a collection of fourteen matching Japanese plates.

Which makers are named on these plates?

No maker names emerged from the Japanese plates in this category at all. They are described by origin, period and decoration instead. Where titles do carry a name it is usually a place: Arita or Hizen for the kiln district, and Meiji or Edo for the period.

How often do these come up for sale?

Fifty-four dealers have listed in the category, and around forty-two pieces come to market in a year. The steady arrival is the single Japanese plate. Chargers, English ironstone and Chinese Imari appear at longer intervals.