Pair of Vases, Unidentified Marking Mid Century Japan?

I purchased these at a thrift store, I can't figure out who designed them based on the markings. They look mid century-ish to me, maybe Japanese?

There is a circle with a K and a B in a square. I love the shape and the ombre effect with the blue gradiating to white. They look great in a modern setting.

Really love them, would like to know the maker!