The largehead hairtail, also known as cutlassfish or ribbonfish (*Trichiurus lepturus*), belongs to the family Trichiuridae under the order Perciformes. It is a medium to large-sized marine fish widely distributed in tropical and subtropical waters, especially in the East China Sea, South China Sea, waters around Japan and the Korean Peninsula, as well as the Indian Ocean.

The hairtail has a long, ribbon-like, laterally compressed body with a silvery, metallic sheen and very few scales. It features an elongated dorsal fin running along its back and a tapering whip-like tail. As a fast swimmer and carnivorous predator, it mainly feeds on small fish and shrimp.

Hairtail meat is tender and rich in protein, unsaturated fatty acids, calcium, and phosphorus. It has a moderate fat content and a delicious flavor, making it a popular fish in many cuisines. It is suitable for various cooking methods such as pan-frying, deep-frying, braising, or steaming. In Japanese cuisine, it is known as "tachiuo" and often appears in salt-grilled dishes or sushi. It is a common and valued ingredient in izakaya and home-style meals, with both culinary and economic importance.