Please add a photo of one piece and the marks on the back. You can do this by using the paper clip icon or ADD FILES button. These features work best on a desktop.
As to the Japan mark. Porcelain will read Japan or Made in Japan for any time period EXCEPT for the years of 1947 through 1952 when the American troops were occupying the Japanese territories; in this case the mark OCCUPIED JAPAN is used.
I will have to opt-out. I cannot know this mark based on a written description without a photo. Another expert will step in to help.