Anatomy and naming

The japanese carcass

Japanese beef butchery is the most cut-specific in the world. The same primal that yields a single named cut in US butchery may yield four or five named cuts in Japanese butchery, each highlighted on the menu of a yakiniku or sukiyaki restaurant. Japanese cut naming uses the muscle's anatomy and traditional eating method as the primary identifier rather than the broad primal location used in Western butchery.

Japanese grading via JMGA covers wagyu marbling at densities far above USDA Prime. The BMS scale runs 1 to 12, with A5 BMS 8 to 12 representing intramuscular fat percentages of 50 to 72 percent — well beyond what US grain-finished cattle typically reach. Region labels below use the standard JMGA primal naming.

Read the JMGA / BMS grading guide

Hover a primal below to highlight it on the chart

Grading · Japan Meat Grading Association

JMGA Japanese Beef Grading and BMS

JMGA grading is the Japan Meat Grading Association standard for Wagyu and other Japanese-origin beef. It combines a Yield Grade (A, B, or C) with a Quality Grade (1 to 5) and a Beef Marbling Standard (BMS) score from 1 to 12, where the highest grade. A5 with BMS 8 to 12, represents the densest, most evenly-distributed marbling in the world commercial market.

BMS 11 to 12

~60 to 72% IMF

Supreme. Almost white with marbling. Approximately 0.5% of carcasses reach BMS 12.

BMS 9 to 10

~50 to 60% IMF

Very-high-grade Wagyu. Exceptional marbling density.

BMS 7 to 8

~40 to 50% IMF

Above-average Wagyu. Rich, dense marbling.

BMS 5 to 6

~30 to 40% IMF

Lower-grade Wagyu. Good balance of marbling and lean.

BMS 3 to 4

~21 to 30% IMF

Minimum threshold for Wagyu qualification. Comparable to USDA Prime.

BMS 1 to 2

under ~21% IMF

Below Wagyu marbling floor. Almost no intramuscular fat.

Visual factors

What graders evaluate

BMS (Beef Marbling Standard), marbling density on a 1 to 12 scale

BCS (Beef Color Standard), lean color on a 1 to 7 scale

BFS (Beef Fat Standard), fat color, gloss, and texture on a 1 to 7 scale

Firmness and texture, assessed visually and by touch

Yield Grade (A, B, C), calculated from carcass measurements; A is the highest yield

From a photo

How MeatGrader applies JMGA Japanese Beef Grading and BMS

MeatGrader applies the JMGA quality factors. BMS, lean color, fat color, and texture, to a retail-cut photograph. The model returns the inferred BMS score and the resulting Quality Grade (1 to 5), tuned to JMGA reference imagery rather than USDA. Yield Grade (A, B, C) is not estimated from a retail-cut photo because it requires whole-carcass measurements.

Read the universal four-factor framework

Cuts by primal