Zabuton

ザブトン means cushion, for the shape of the slab it is cut into. It comes from the chuck, the shoulder, and is built around the serratus ventralis, a muscle lying under the shoulder blade against the ribs. That location is the whole story of the cut: it is deep enough in the shoulder to be shielded from the work the outer shoulder muscles do, so it stays tender while sitting in a heavily marbled part of the animal.

In U.S. fabrication it overlaps with what sellers market as a Denver steak, although the two are not guaranteed to be cut identically. Overlap is the honest word. The underlying muscle is the same; how much of it a given seller takes, and how it is trimmed, is not standardised between the two names.

The chuck is a working region and most of it sells for less than the loin, which is why zabuton is often the best value on a Wagyu menu. It carries marbling comparable to cuts that cost considerably more, and it is not competing with the ribeye for the same buyers because most people have never heard of it.

That gap is closing as Denver steak becomes a familiar name on American menus, and it is worth being clear-eyed that a Wagyu zabuton is no longer cheap in absolute terms. The claim is relative: for a given marbling score, this is usually a lower price per ounce than the loin cuts.

Ask which muscle, because chuck is a large primal and several cuts come out of it that eat quite differently. A seller naming serratus ventralis, or naming Denver steak alongside zabuton, is being specific. A menu writing only chuck is not.

Then the usual two questions: origin and grade. The grade is worth a particular note here, because the marbling score behind it was read at a cross-section through the rib, not through the shoulder. It is a fact about the carcass, and marbling does vary between muscles.