how do the japanese prepare that raw beef and egg dish which i like so much?

When I worked in Tokyo Japan in the late 1980's they used Kobe or Waygu beef, I even had horse and whale meat done the same way, it is essentially a Japanese Steak Tartar, you use Japanese mustard, Mirin cooking wine, soya sauce, chopped shisu leaves, I like it spicy so I add Tabasco, some add pepper I use Japanese Mountain pepper buds, only one egg yolk is necessary, if this is made ahead, keep it chilled, if you do not want to go to all this work, Kewpie Japanese Mayo, Dijon mustard, white wine and chopped parsley can be substituted, I have had it wrapped in seaweed and served with rice crackers to.

Recently O-157 infection is a very serious health issue and the cooking of raw meat is being strictly regulated in Japan. The authority recommends not to eat raw meat (including beef tartar, since a lot of people got sick after eating beef tartar in Japanese yakiniku chain stores that served poorly prepared beef tartar).

The safe way to prepare tartar steak is to use fresh beef in a loaf (not already-ground beef), properly stored in a low temperature. Cut out all the surface meat with a clean knife and a cutting board and only use the meat inside for your tartar. After chopping beef in tartar form you should serve it immediately.

Note that the disease causing bacteria live in the intestines of the cow, so never buy the gound beef for your purpose. They mince various parts of beef meat together and the risk of contamination is very high.