When I went to Osaka last month, I bought some A5 (the best) grade Wagyu before I left.
There are 4 different species of Wagyu and the best one is called Kuroge wagyu(黒毛和牛).
Even A5 Wagyu have different grades and are prcied from around 1500 yen/100gm to over 5000 yen/100gm depending on the cut and the BMS (Beef Marbling Standard) grading. BMS is scaled from 1 to 12. A5 Wagyu grade must achieve a BMS value of at least 8 or more. BMS value of 12 is extremely rare.
Besides Wagyu beef, Sukiyaki is also eaten with Japanese mushrooms and vegetable.
After the Wagyu beef is cooked in the Sukiyaki sauce, it is dipped in beaten egg before eating.