"Nankotsu" means cartilage, and in Japanese cuisine, it mainly refers to chicken cartilage. Among the various chicken cartilage, knee cartilage (ひざ軟骨) and breastbone cartilage (やげん軟骨) are commonly used in cooking.

Knee cartilage is often made into a dish called "karaage" (唐揚げ), a type of deep-fried dish. This dish is known as "Nankotsu karaage" (なんこつ唐揚げ), and it is a popular menu item frequently found in izakayas (Japanese-style pubs). It has a crunchy texture and is an excellent accompaniment to alcoholic beverages.

Another type of cartilage is breastbone cartilage. It refers to the long triangular-shaped soft bones found in the chicken breast portion, which we often encounter when eating chicken dishes like chicken or samgyetang. This cartilage is also used in cooking, and it is grilled with some meat attached to it, maintaining its long shape. You can find it on the menu at yakitori restaurants.