Thanks bossyvossy! I will look into that!

No...I believe you were closer with Japanese....or perhaps Chinese...perhaps 18th century....and that's one reason they have no mark.
VERY nice!!

A little searching finds that they likely ARE Japanese and made in the Arito area...Imari plates. They were not always marked.
They are the Porcelain that Delft pottery was imitating.
Note....Delft is pottery and chips rather easily, while this is porcelain and high fired and resistant to chipping.
Google blue and white Imari plates to see lots of examples like yours.

Look at this link on Ruby Lane to see a plate with a similar painted design on the underside and the same incised mark - Antique Blue & White Stencil Ware Japanese Imari Plate Meiji Period Children - c. 1900's, Japan

"Lovely blue and white Meiji period (1868 to 1912) stencil ware Imari
plate decorated on the front with children around a tea table and on the
back with a flower border. It is marked on the underside with an
incised Dai Nippon [Great Japan] mark consistent with the nationalism of
the Meiji period (1868 - 1912)."

But the type of pattern is very different.

Yes, but I wanted to point out that the incised mark on the back is identical to 2 of her plates, to give her a bit more information on them. "It is marked on the underside with an incised Dai Nippon [Great Japan]
mark consistent with the nationalism of the Meiji period (1868 - 1912)"

That mark is not what I know as "dai Nippon".

I think you're right there. I didn't think the Dai Nippon mark was correct as that looks more like a Japanese pictogram/letter and your mark doesn't. But it does look like the Fukagawa Orchid.

Spot on!