I bought this raw ore and flatened one side from Watanabe. He claims its from Kouzaki. It has a crack on the side I flatened (I didnt notice any misbehavior of that crack on my edge ). I laquered other sides heavily to keep it compact. Still not decided how to cut it and even if. Its not completed. But Already works! Its a gorgeous 2000-4000 medium grit I bought him Ikarashi to help to get from AI1000 That thing has 4,5kg Its harder Aoto and needs time to slury. Many goma dots and nice navy blue. So far as busy chef I use it every day and it keeps mi knife bitty sharp to get me through 50kg of meat.