Arita tea cup

This Arita tea cup is just over 2.5" in diameter and just under 2.5" high. It has a chatty marking on the bottom which may be both a kiln and a potter/decorator mark. The Japanese characters on the label say "Arita Ware".

It is a peculiar style that is typical of some Arita cups, both in construction and decoration, containing a vertical rib on the side of the cup. I have seen several styles of these cups some with teapots; this style, half globe lidded cups, handled cups, etc., all with the external vertical ridge and close variations of this decoration.

When I found this cup, I looked at a lot of examples but do not remember if I came to any conclusion as to which kiln makes this style. I suspect that this style is associated with a single kiln or potter. It is spiffy little cup.

Unsolved because I don't know which kiln made it or the story behind the construction. I have not seen any other Japanese cups like this.