Vintage Japan Tea Cup and Snack Plate

Vintage 40's fine china tea cup and snack plate set. Rare item. Iridescent white inside cup, iridescent tan, green with floral blue bird pattern on the rest. Cup is 2 1/4" high 2" diameter. No chips or cracks. There is a little circle on the plate(see pic). I don't know what it is or if it was like that originally.