This is a good example of a section cut of hon maguro tuna. On the one side of the belly you have the o-toro, the fatty tuna and on the other side you have the akami, the red part of the belly’s upper side and in between chu-toro. The diagram below shows the sections 0f the tuna’s belly, however the belly is long and wide and often the size of a human or much more. So the belly section of this tuna photographed is after the first part at the forefront of the tuna.