I am so interested in cooking and I've always wanted to cook with Kobe beef and have heard its delicious. 
Those cattle go back a long ways. They were brought to Japan from China around the 2nd century AD, around the same time as the cultivation of rice.
Oh wow. I didn't realize that. Do the cattle eat a special diet? 
They are grain fed. There was a ban on them being imported for awhile,  and just recently have been allowed to be imported to the US in 2012
I see. Why were they banned at all?
It was to prevent an outbreak of disease. There are 4 breeds -- the Japanese Black, the Japanese brown, the Japanese Polled and the Japanese Shorthorn
Is there any one breed that is better than the other? Or are they pretty similar?
Japanese Black
The Japanese Black (, Kuroge Washu) is a breed of Japanese beef cattle. It is one of six native Japanese cattle breeds, and one of the four Japanese breeds known as wagyū, the others being the Japanese Brown, the Japanese Polled and the Japanese Shorthorn.
All wagyū cattle derive from cross-breeding in the early twentieth century of native Japanese cattle with imported stock, mostly from Europe. In the case of the Japanese Black, the foreign influence was from European breeds including Braunvieh, Shorthorn
Kobe beef
Kobe beef is also called , or in Japanese.
History.
Cattle were brought to Japan from China at the same time as the cultivation of rice, in about the second century AD, in the Yayoi period. Until about the time of the Meiji Restoration in 1868, they were used only as draught animals, in agriculture, forestry, mining and for transport, and as a source of fertiliser. Milk consumption was unknown, and – for cultural and religious reasons – meat was not eaten.