I first came across the Kusshi a few years ago at the Swan Oyster Depot-my favorite place for oysters, cherry stone clams, crab & perfect cup of clam chowder in San Francisco. Kusshis are sooooooo good, I would often walk over to Swan and have them for breakfast (best time to go to avoid the crowd.)
Kusshi means "ultimate" in Japanese and they really are - not too big & not too small like the Kumamoto. They have a deep cupped shell and the oyster is plump and meaty, mineraly & sweet. Kusshis are cultured in British Columbia.