My Budapest preference for Japanes has been for Kyoto for years. Then Kyoto changed name to Tokyo and went to dogs right thereupon. My enquiries in the community bore fruit, and I tried Fuji. Unlike the former one, it is quite remote, up in the Buda hills, some twenty minutes drive from the central hotels during normal hours. Parking within 100 meters easy. Nothing spectacular either from without or within. However, it is a truly commendable place for learned sushi fans. It offers three additional dining rooms for traditional Japanese dining of smaller parties beside the main dining hall in the European style.
Winelist is hardly impressive, but so are almost all in the city. Service quite mediocre. Kaiseki tasting menu far from what you get in an average kaiseki home in Japan, lacking both many original ingredients and perfection in execution. Toro sashimi disappointing with highly unusual herbs overcoming the basic flavor that one looks for in toro – and expensive. However, sushi was one of the best I have ever tried, Japan with Tsukiji spots included. A 15- on a 1-20 scale, a restaurant I shall definitely return to when in Budapest.
If you want to eat proper, almost Japanese »Japanese food« in Budapest, I doubt you can find a better place, provided you take time for the experience. Also a lot of Japanese folk seem to frequent the place, confirming my statement. Beware, expensive for Budapest standards (90 per head for a quite serious dinner with only one of two actually drinking wine).