This reminds me of the superb “filet de boeuf’s” end cut. It comes from a two-hundred fifty kilo tuna caught off the north shores of Japan. The fish is divided between the finest sushi chefs in Tokyo and elsewhere. The chef walks away with a small 7-kilo piece which includes the belly and the underside.

The tuna gets devoured quickly over the period of a week and a half. It ferments and color changes, it gets darker. The fatty parts remain a deep color and as you can see, this is a split cut. The grainy fat, instead of a broader fat that you often find in o-toro that is more belly-side but is non-less than sensational.