I order fresh fish from Tsukiji market once a month and recently I bought Seki Mackerel , which is mackerel from Saganoseki. The fish is considered the best example of saba available. Just as the way the Chef Shiro from Shiro's taught me, I filleted the fish, sprinkled salt like snow, and left the fish for 2-3 hours. After leaving the fish for 20 minutes in water, I cut the skin off and left it another 1-2 hours in rice vinegar. It turned out to be wonderful!!