A large tuna distributed in the tropical and temperate waters of the Pacific Ocean, including the coasts of Japan. The standard name in Japanese is "Kuromaguro" (黒鮪), but it is generally distributed under the name "Honmaguro" (本鮪). Typically, when fully grown, it can reach 3 meters in length and weigh up to 300 kilograms. Among tunas, the bluefin tuna is the largest and most expensive high-grade species, with prices reaching tens of millions of yen per fish. In Japan, bluefin tuna caught using the "Ipponzuri" (一本釣り, single-hook fishing) method is considered the highest quality. There are several theories about the origin of the name "maguro" (tuna). One theory is that it is called "maguro" (眼黒) because of its black eyes. Another theory is that because its back is black, it looks like a small black mountain from the ship, hence "maguro" (真黒). Another theory is that it turns black when left at room temperature, hence the name maguro.