Chu-Toro - Meium Fatty Tuna 

ChuToro is the moderately fat meat of a tuna.  A blue fin tuna yields Akami (red meat), Chu-Toro, and OhToro (pink meat with a large fat content), and chu-toro is usually found near the skin on the back and belly.  Many connoisseurs prefer chu-toro because it combines the lighter but deep, slightly bitter flavor of an akami with the sweet tenderness of an oh-toro.  Sometimes you will find a cut of chu-toro with a gradation of red from the deep red to pink (lean to fatty). 

“Many think the oh-toro from belly of a tuna is the best, but I love the chu-toro from near the back of the body.  It has great flavor and not stringy at all, just smooth.”  Chef Maeda