Senmai

The beef's third stomach, its name said to come from the many stacked folds inside. Low in fat with a crisp, springy chew — among the plainest-tasting of the offal cuts. Each fold is thin, and the layered ridges are said to give a distinctive, stacked kind of chew. As the third stomach, its folds are said to widen the surface area available for digestion. Among the stomachs, it's said to have an especially intricate structure.

The white version, with its black outer skin removed, is the one mainly sold. It's sometimes eaten raw or dressed with vinegar, and how carefully it's trimmed is said to directly shape its texture; at yakiniku it's often barely seared. It's often served finely sliced with a knife, its whiteness and crisp bite the qualities most prized. When served raw, freshness management is said to matter especially, making a trusted supplier essential.

Its low fat sets it apart among offal cuts, and it's often said to serve as a palate cleanser amid the richer flavors of a yakiniku meal. It's one of the few offal cuts eaten raw or dressed with vinegar, more like sashimi than grilled meat. In a genre built around richness, this cut is said to carve out its place by leaning the other way, into leanness. It's often dressed lightly with ponzu or sesame oil, a way of eating said to let the texture of the meat itself come through.