Alas, a very good USDA Prime steak could meet a higher class in Japan.

FORBES: Kobe Beef Is Back! New Rules Allow Some Japanese Beef In U.S.

Note that these additional grades are not mere sub-sects of what USDA Prime would be, but have more constrictive requirements.

FORBES: Kobe Beef Is Back! New Rules Allow Some Japanese Beef In U.S.

This is why they have used the name to sell what is probably another breed of cattle that is USDA Prime.

FORBES: Kobe Beef Is Back! New Rules Allow Some Japanese Beef In U.S.

This is NOT to say that USDA Prime could not meet them, because obviously the minimums for USDA Prime are just that, minimums for that particular grade.

FORBES: Kobe Beef Is Back! New Rules Allow Some Japanese Beef In U.S.

Dry aging is so important that it supplants USDA grades: dry aged choice beef tastes much better than the highest grade, prime, un-aged.

FORBES: Steaks Worth Bragging About Are Dry Aged