Tamagokaké gohan (egg on rice) has long been popular in Japan. Tamagokaké gohan is simple to prepare. Simply crack a raw egg over a bowl of freshly cooked rice and drizzle a little soy sauce on top. That’s all there is to it, and it’s a great treat.
When eating, mix lightly and eat with chopsticks or a spoon. Although egg on rice is not served in restaurants, it has been a common way of eating eggs in Japanese households for a long time.
You may be concerned about whether it is safe to eat eggs raw, but there is no problem with eggs sold in Japan. The expiration date of eggs sold in supermarkets and convenience stores in Japan sets the date by which eggs can be eaten raw when stored at room temperature.
Therefore, there is no problem with eggs that are within the expiration date or eggs that have been stored in the refrigerator. The possibility of salmonella in eggshells is very rare (around 0.00003%), but if you are concerned, it is safer to wash eggs under running water before cracking them open.
I do not know if eggs sold outside of Japan are safe to eat raw. If the eggs are freshly laid or not old and refrigerated, I guess they are safe if washed in water, but I cannot guarantee it.
Any soy sauce can be used for egg on rice. In Japan, there are several soy sauces available specifically for use with egg on rice. I recommend soy sauce with dashi. Dashi soy sauce can also be used to flavor Udon noodle soup or simmered dishes.