The name is derived from the fact that the land and roof were triangular in a well-located market adjacent to Otaru Station. Not to mention local customers, there are also many tourists who come to pick souvenirs. In addition to the fresh seafood taken near Otaru, there are many shops that sell salt and dried fish. About 20 stores run the house, and most stores can ship nationwide. In addition, there is a dining hall in the market where you can taste seasonal sea products, such as sea urchin bowls and ikura bowls, as well as seasonal grilled fish.