This is something special: sushi for breakfast out at the fish market. It takes an effort to get here, but the sushi is excellent and you can wander around the market before and after eating. Sushi-no-uo-masa is smack in the middle of the stalls that lie between the two restrooms at either end on the ground floor of the Maruka Oroshiuri Centre.
Not to be confused with Ni-jō Ichiba, the Central Wholesale Market (Chūō Oroshi-uri-ichiba; 中央卸売市場) is a 10-minute walk from either the subway or the train station.