BMS Score (Beef Marbling Score)
The Japanese 1–12 numerical scale used to objectively measure intramuscular fat in wagyu beef, where 12 is the highest possible marbling.
The BMS (Beef Marbling Score) is the numerical scoring system used by the Japan Meat Grading Association to evaluate marbling in beef on a scale of 1 to 12. It's the most precise marbling measurement system in the world, and if you're buying wagyu, it's the single most important number to know.
The Scale in Detail: - BMS 1: Essentially devoid of marbling. You'd never see this sold as wagyu. - BMS 2–3: Trace to slight marbling. Comparable to USDA Select to low Choice. - BMS 4–5: Small to modest marbling. Upper USDA Choice territory. - BMS 6–7: Moderate to slightly abundant marbling. This is where wagyu starts to feel like wagyu. Low A4 grade. - BMS 8–9: Moderately abundant to abundant. A5 territory begins at BMS 8. Distinctive webbing of fat throughout the meat. - BMS 10–11: Very abundant. The meat takes on a pink-white appearance. Extraordinary richness. - BMS 12: Maximum score. More marbling than lean. The meat looks almost white with streaks of red. Rare even in Japan.
How It's Measured: At the 6th/7th rib cross-section, trained graders and camera systems evaluate the percentage of intramuscular fat, its fineness, and its distribution. Unlike the USDA system (which relies on human graders making subjective assessments), the Japanese system incorporates camera technology for greater objectivity and consistency.
BMS vs USDA: The scales don't map perfectly, but roughly: - USDA Select ≈ BMS 1–3 - USDA Choice ≈ BMS 3–5 - USDA Prime ≈ BMS 5–7 - Japanese A4 ≈ BMS 6–8 - Japanese A5 ≈ BMS 8–12
Why You Should Always Ask: When someone sells you "wagyu," the BMS score tells the truth. A BMS 4 crossbred sold as "wagyu" and a BMS 11 fullblood A5 are in completely different galaxies of eating experience — and should be in completely different price ranges. Any legitimate seller will proudly share the BMS. If they can't or won't, walk away.
Related Guides
What is Wagyu Beef? A Butcher's Honest Guide
Wagyu is the most misused word in the meat industry. Here's what it actually means, how to tell real from fake, and whether it's worth your money.
Understanding Marbling: Why Fat Equals Flavor
Marbling is the single most important factor in how a steak will taste. A veteran butcher explains the science, the grading, and why genetics matter more than anything.
The Truth About Kobe Beef: Myths, Facts, and What You're Really Eating
Most "Kobe beef" sold in America isn't Kobe at all. A veteran butcher separates myth from fact and tells you what you're really paying for.