I assume not only in Japan but also exists anywhere in the world but there is a dish in Japan which does not exist in the "original" country,
The dish is called Tenshinhan in Japanese, and can be translated into Tianjin rice in English. You can find this dish in all most all Chinese restaurants in Japan and the it is Chinese style omelet with crab meat on rice. The sauce can be up to the restaurant. it can be sweet and sour or much more transparent color. Actually the Chinese omelet with crab meat exists as a dish in China but it does not come on rice.
Then, Tianjin is a name of a city in China, relatively close to Beijing. It is not well known in Europe as like other Chinese cities but the population is more than 5 million and it has a special status for its municipality. In this case, I think everyone will consider that Tianjin is the home of the Chinese omelet with crab meat but it is not true. The omelet is Cantonese dish and Tianjin is far away from Canton province. Anyway, Tianjin rice is delicious and worth to order it.