Japanese Wagyu Grading Explained: A5, BMS and the 15 Grades
Chia sẻ
"A5" is the most famous label in beef. But what does it actually mean? This guide explains Japan's grading system in plain English, so you know exactly what you are buying.
Who does the grading?
Every carcass in Japan is graded by the Japan Meat Grading Association (JMGA), an independent body. Its graders inspect the carcass at a cut made between the 6th and 7th ribs. The grade is stamped on the carcass and recorded.
A Wagyu grade has two parts: a letter and a number. In "A5", the A is the yield grade and the 5 is the quality grade.
Part 1: the letter (yield grade)
The yield grade measures how much usable meat the carcass gives. It is worked out with a formula using measurements such as the size of the rib eye muscle, the thickness of the rib and the thickness of the outer fat.
| Yield grade | Estimated usable meat | Meaning |
|---|---|---|
| A | 72% or more | Above standard |
| B | 69% to under 72% | Standard |
| C | Under 69% | Below standard |
The letter says nothing about taste. It is about how much meat the farmer and butcher get from the animal.
Part 2: the number (quality grade)
The quality grade runs from 1 (poor) to 5 (excellent). Graders score four separate things, each from 1 to 5:
- Marbling, measured with the Beef Marbling Standard (BMS)
- Meat colour and brightness, measured with the Beef Colour Standard (BCS)
- Firmness and texture of the meat
- Fat colour, lustre and quality, measured with the Beef Fat Standard (BFS)
Here is the key rule: the final grade is the lowest of the four scores. A carcass scoring 5 for marbling, 5 for colour, 5 for texture but only 4 for fat quality gets a 4. To earn A5, a carcass must score top marks in every test.
The Beef Marbling Standard (BMS)
Marbling is scored on a scale of 1 to 12. Graders compare the meat with official reference images. The BMS number then decides the marbling part of the grade:
| BMS number | Marbling score | Description |
|---|---|---|
| 8 to 12 | 5 | Excellent |
| 5 to 7 | 4 | Good |
| 3 to 4 | 3 | Average |
| 2 | 2 | Below average |
| 1 | 1 | Poor |
So an A5 always has a BMS of 8 to 12, and an A4 has BMS 5 to 7 (or higher marbling held back by another test). BMS 12 is the highest marbling score possible. Other countries, such as the USA and Australia, use their own marbling scales, so their numbers can't be compared directly with Japanese BMS.
The other three tests
- Colour (BCS 1 to 7): from pale red to dark red. A bright, clear cherry red in the middle of the scale scores best.
- Firmness and texture: graded from very good and very fine down to inferior and coarse. Finer grain means a silkier bite.
- Fat (BFS 1 to 7): from white to yellow. White, glossy fat scores best. Fat quality strongly affects flavour and melt.
The 15 grades
Three yield grades times five quality grades gives 15 possible grades:
| 5 | 4 | 3 | 2 | 1 | |
|---|---|---|---|---|---|
| A | A5 | A4 | A3 | A2 | A1 |
| B | B5 | B4 | B3 | B2 | B1 |
| C | C5 | C4 | C3 | C2 | C1 |
A5 is the top of the 15. We only sell A4 and A5.
Three things most people don't know
1. The grade belongs to the whole animal, not the cut
Graders look at one place: the rib eye at the 6th and 7th ribs. That grade then applies to every cut from the carcass. So an A5 shank or A5 top round is genuinely A5 beef, but it will not look as marbled as an A5 sirloin or ribeye. Leg and shoulder muscles work harder and naturally carry less marbling. That is normal, and it is why those cuts cost less.
2. A5 is a range, not a single level
A5 covers BMS 8 to 12. A BMS 8 and a BMS 12 steak are both A5, but the BMS 12 is noticeably richer. If you see a BMS number on a pack, it tells you more than the grade alone.
3. B5 can be just as delicious as A5
The letter is about yield, not eating quality. A B5 carcass has the same top-quality marbling, colour, texture and fat as an A5. It just gave the butcher a little less meat. This is also why Kobe beef can be A or B: see Kobe beef vs Wagyu.
What this means when you buy
- Look for the grade and the BMS number. "A5, BMS 10" tells you much more than "A5".
- Ask for the 10-digit cattle ID. It lets you trace the animal on Japan's official register. See how to buy real Japanese Wagyu.
- Choose the grade for the occasion. Read A4 vs A5.
