Hamburg is made from ground meat with onion, egg and breadcrumbs. It is a flat circular shape and thicker than a patty in hamburgers. Many restaurants serve various kinds of hamburgs and sauces. Cheese hamburg is a famous choice. The cheese can be served in two ways: as a topping or stuffed inside the meat. Handmade hamburg is really delicious and is different from frozen ones sold in supermarkets. One of the most famous hamburg restaurant chains in Japan is bikkuri-donkey. Its interior design is American style.
You can see some photos under the link:
It is a hamburg topped with terimayo sauce.
Terimayo sauce is a mixture of teriyaki sauce and mayonnaise.