There are many reasons for heading across the Sumida River to Tsukishima. Most of them involve monja, those griddle-splattered, dogs-dinner “pancakes” that are Tokyo’s unconvincing answer to the okonomiyaki of western Japan. The one blessed anomaly is Ajisen.

It’s not the sole izakaya (dining pub) in the area. But it really is the only one that’s worth a special journey to those few square blocks of waterfront landfill. Especially on a chill, damp evening in early spring.

Ajisen stands on a quiet residential street, away from the bright, theme-park ambiance of Tsukishima’s main drag. That does not make it a hidden gem. Quite the opposite: For years now it has been vaunted alongside the best of the city’s izakaya, rated as highly for its sake cellar as for its excellent seafood.

Over a decade since it first opened, Ajisen hardly seems to have aged a day: the trademark snail-shaped lamp on its outer concrete wall — along with a smaller version on the ground, the only clues that you’re in the right place; the array of sake magnums on the shelf running above the counter looking into the open kitchen; the hand-written menu slips plastered on the bare walls. Little has changed over the years.

Thankfully, the same still applies to the food. It’s not just that owner-chef Shinichi Araki has a hotline to the best and freshest in nearby Tsukiji market. He understands exactly what’s at the peak of its season, and how to prepare it.

Don’t worry if you can’t read the Japanese menu. There is only one phrase you really need to know: sashimi moriawase. Araki’s top-end mixed seafood platter is a classic, an artistic array of 10 or so different kinds of gleaming, pristine fish, crustaceans and shellfish.

Sweet ama-ebi shrimps, pale yellowtail belly, red akami tuna and more: These are not the rarest, priciest cuts, but they are still top quality. And that’s the whole point. Ajisen remains as affordable as it is down-home friendly and casual.

There’s more to come. A separate plate arrives, covered with orange uni (urchin), beautifully arranged on a jade-green leaf of sasa bamboo grass. The delicate, briny flavor and creamy texture of these morsels shipped down from Hokkaido are about as good as it gets.

Winter specialties such as shirako (cod milt) and kanburi (winter yellowtail) are finishing now. Soon Araki will be slicing up hatsu-gatsuo, the new-season skipjack, either on its own or as part of the sashimi plate.

His shirasu, tiny young sardines served raw with a citrus ponzu dip, are always super-fresh. He serves a very fine anago no shirayaki (lightly grilled, unseasoned conger eel). The tempura is always good, especially if there are spring sansai (wild plants) on the menu. And his homemade jumbo-sized satsuma-age (deep-fried fish cakes) are among the best in their class in Tokyo.

So too is the sake selection. Araki was one of the pioneers in serving premium ginjōshu sake. Alongside more established brands such as Kubota or Kokuryu, he also stocks obscure brews from little-known regional sake houses. Ask for recommendations; there are always discoveries to be made.

Ajisen, 1-18-10 Tsukishima, Chuo-ku, Tokyo; 03-3534-8483; 5:30-11 p.m.; closed Sun., Mon. and hols.; nearest station Tsukishima; smoking permitted; ¥3,000 per head (plus drinks); no cards; Japanese menu; a little English spoken. Robbie Swinnerton blogs at www.tokyofoodfile.com.

Ajisen Restaurant Page Ajisen Name (J) 肴や味泉 Dinner price range ¥5,000 or more Cuisine Japanese Keywords seafood, tofu Smoking Smoking permitted Reservations Recommended Area East Tokyo Address 1-18-10 Tsukishima, Chuo-ku, Tokyo Address (J) 東京都中央区月島1-18-10 Stations Tsukishima Station Telephone 03-3534-8483 03-3534-8483 Hours 5:30-11 p.m. closed Sun., Mon., holidays Payment information Cash, Credit Card Map

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