Beyond Prime

Marbling is the most prized aspect of Japanese beef and breeders go to great lengths to create intense patterns that make the meat literally melt in your mouth. In fact, the beef grading systems in most countries are directly related to how much marbled fat is present.


In order to achieve the minimum quality grade for Wagyu in Japan (BMS 3), meat must be at least 21% marbled fat (IMF) and, the other end of the scale a BMS 12 grade carcass has graded up to 72% IMF.


In contrast, USDA’s highest grade; Prime is approximately 11% marbled fat (IMF). Only 3% of the beef in the USA is designated Prime, whereas 90% of Wagyu-influenced cattle (50% or higher) achieves a Prime score.


While Japan, the US, Australia, and other countries around the world use IMF as a critical factor for grading, each has their own scale and judging criteria.

Japanese Grading Scale

Japan uses a very specific and comprehensive grading system which combines a Meat Quality Score (scoring between 1-5 with 5 being the best) and Yield Score (scoring A-C, with A being the best) for an Overall Meat Score.

Meat Quality Score is based on four factors – Beef Marbling Standard (BMS), Color & Brightness, Firmness & Texture, and Luster & Fat Quality. Yield Score is determined by the estimated percentage of edible cuts. Only Fullblood Wagyu is can receive a Yield Score A.

BMS is based on not just the IMF percentage but takes into consideration the firmness, coarseness, and coloring of the marbling. There is a minimum level of IMF that must be achieved in order to a specific score, but the evaluation of other factors is included to determine final BMS. The average BMS throughout Japan is 5.2-5.7, and only about 0.5 percent of all beef achieves a 12.

Japan made a significant update to their rating scale in 2008, making it much harder to achieve the higher score potential. For example, a BMS 6 or 7 from the old scale would rate at a BMS 3 on the new scale. However, the pre-2008 scale is still referenced in most of the world.

USA Grading Scale

In the United States, the USDA grades beef using IMF percentage, color, and fat distribution that rates marbling on three levels—Select, Choice, and Prime. If there is very abundant marbling, the beef gets a Prime++ grade.

At Lone Mountain our beef averages about 33% IMF, which puts our beef approximately at a BMS 4 – 5, and Prime++ USDA ranking.

Grading Technology

Up until recently you could not compare US graded meat products with the Japanese grading but with the recent development with a camera based system, that comparison has become a reality.

Lone Mountain Cattle were the first in the US to acquire such technology out of Japan and the data generated from the camera has underpinned Lone Mountain’s genetics and meat program ever since.