All of these are natural whetstones from Kyoto. They are Sujaka. The surfaces other than the whetstone faces are protected. The long white Sujaka whetstone does not have a finished surface. The blue Sujaka also has some areas where the surface is not finished. The blue Sujaka is medium-hard and I think it's an easy-to-sharpen whetstone. Please take a good look at the other images before purchasing.