Sushi Sei is an upscale Japanese restaurant located a bit outside the city center in Buda. Popular types of raw seafood dominate the menu: sashimi, maki (cut sushi rolls), nigiri (mounds of rice topped with fish filet), and chirashi (fish scattered over vinegared rice in a bowl). Besides the usual tuna, salmon, and prawn options, the impressively broad fish selections also include raw eel, sea bass, octopus, squid, and salmon roe.
The chirashi bowl (€23) is a good way to sample a cross-section of the most interesting cuts of fish. During the summer, cold soba (buckwheat) noodles dipped in a dashi, soy, and mirin-based sauce (€8) are a reviving way to finish the meal. Although mainly a seafood restaurant, non-seafood fans can order excellently-prepared tonkatsu (€8), karaage (€8), and yakitori (€7).
I found Sushi Sei's atmosphere a bit cold and uninviting - some of this has to do with the sheer size of the venue, which rarely gets more than half full. But if you're looking for a fancy meal of sushi, Sushi Sei can be a good option. It's slightly cheaper than Fuji, a comparably upscale sushi place not far from it.