Okonomiyaki is native to the Osaka and Hiroshima areas of Japan. It is a pancake made with potato flour, and containing cabbage, and assorted other vegetables and meats, and in the Osaka variation, noodles. Once cooked, the pancake is topped with brown sauce, mayonnaise and bonito flakes or tiny flakes of nori (seaweed), which appear to dance as the heat rises around them. If you are a connoisseur of Korean pa-jeon and Vietnamese banh xeo, then okonomiyaki is a must try dish, along with takoyaki, small dough balls containing octopus that are often sold from carts on the street.
You can easily make okonomiyaki at home following this recipe or many like it. Often at restaurants, you will be given a bowl of raw mix, and cook it youself on a hotplate at the table. At other restaurants, you might sit at a counter in front of the chef as they cook in front of you, as common in many types of Japanese restaurants, and probably the closest you'll come to "teppanyaki" style cooking in Japan.