@marcyvq
@fdmz
I've had this on gyudon (I forget the exact name) and normally, I cook my eggs until juuuuuust shy of rubbery without any hints of runny yolk, however, I can tell ya right now that that was one of the best things I've ever eaten. The egg kinda cooks into the rice thanks to the heat and steam from the rice and beef, becoming this thin coating of egg on the grains and strips of meat, while some mixes with the juices of the meat and the sauce, becoming something akin to an impromptu cabonara-like silky sauce.
My bet is that there's something about the rice that the Japanese use in particular that allows this to work.