Oyakodon

Oyakodon is a bowl of rice topped with simmered chicken and egg.
Japanese word, "Oyako,親子" means parents and child.
In the name of the dish, chicken is compared to parents, and egg is compared to child.

We usually simmer bite-size cut chicken and sliced onion in mildly sweet soy sauce based broth.
Add beaten egg to them, and simmer until egg start to harden.
Put them on hot rice in a bowl.
Finally, put nori or mitsuba-leaf on it.

Tendon (Tempura Bowl)

Tendon is a bowl of rice topped with tempura.
Usually It is poured with mildly sweet sauce (Tare) which is made from dashi-stock, mirin, soy sauce, sugar and so on.

Prawn is most popular ingredient for Tendon.
In this photo, tempura topped on the rice, are prawn, pumpkin, and small sweet green pepper.

Gyudon

It is called "Beef bowl" in some country.
"Gyu" means beef, and "don" means a bowl rice topped with some ingredients.
Gyudon is a bowl rice topped with thinly sliced beef and onion, simmered in mildly sweet flavored, soy sause based broth.
We usually put BeniSyoga(pickled ginger) on it, befor we eat it.
Gyudon is also popular as a dish of fast food restaurant.