Bringing out the best in fish through fermentation: that's the driving idea behind this new Marunouchi restaurant. Using fish and fermented seasonings from ports across the country, Nippon no Hitosara has added some inventive quirks to its menu as well: definitely try the sashimi with shiboritate kiage shoyu, meaning freshly pressed, unpasteurised and unfiltered soy sauce – it's been fermented but not strained. Soy sauce (and the fish, of course) doesn't get much fresher than this.
If you want some veggies instead, the Asatore yasai to sanshu no hishio (morning vegetables with three types of paste, made with homemade jang (think miso paste)) is a good bet, while the Futakuchi hakko tai chazuke, Thai-style seabream sashimi with fermented soy sauce on top of rice with tea, is another fishy winner.
Their lunch sets look very good too, although you might have to get there early to grab one of the ¥1,000 teishoku: two of the sets, including the rather scrumptious Ryukyu-don – despite its Okinawan name, this is an Oita speciality, a soy- and mirin-doused sashimi donburi with sesame, shiso and green onions – are only served to ten customers daily.