Let us take a step back and answer the question what are Wagyu? Wagyu (pronounced Wog-you) which means nothing more that Japanese (Wa) Cow (gyu) are a breed of beef cultivated from a mixture of Asian cattle (primarily Tajima) for over 3500 years in, where else, Japan. Japanese ranchers took special care and pride turning these draft cows into a breed that is renowned worldwide for its amazing flavor profile.
How can draft animals taste so amazing you might ask? FAT! Specifically, their inter-muscular fat cells. The same fat cells that provided these work animals with readily available energy source. And the same fat cells that produces the amazing marbling that has become the signature of the Wagyu.