Identify Japanese cups

Hello everyone,

These are very pretty Made in Japan pottery cups. They are made of tan clay with an interior white swirl and blue glaze outside with bamboo decorations. They are marked

but I cannot find the same mark online (I checked out the Gotheborg site, but nothing matches). Is there something special about the tan clay/white swirl? Any idea of age? They measure 3 1/4" wide x 2 1/16" h. Are they for serving tea or rice? Thanks for any help you can give.