A plate of fluke, scallop, and yellowtail. | Tierney Plumb/Eater DC Tysons got a taste of Tokyo last spring with the arrival of reservation-only Naisho Room atop the Watermark hotel. The sky-high speakeasy, which translates to “hidden” in Japanese, is tucked inside the hotel’s gym. Onc e you find the weightlifting machines, look for the “bouncer” dressed like a fitness instructor. The hostess stand is outfitted like a sauna. James Kim leads the19- to 22-course omakase menu ($202), available Wednesdays to Saturdays. He  honed some serious knife skills working at Asian standouts in San Francisco like three-Michelin-starred Benu. What to order The steady stream of courses includes a few hot and cold plates like an oyster shooter featuring Okinawa seaweed and delightfully silky egg custard with snow crab. Tokyo’s famed Toyosu Fish Market supplies most of the seafood selection: big fin squid, sea urchin, rockfish, black cod, striped jack, seabream, scallops, fatty tuna, and monkfish liver, to name a few. Fish gets the aged and torched treatment, as does wagyu, each bite artistically presented on decorative plateware next to clumps of freshly grated ginger.  A stellar sake list, which includes stark-white bottles of snow-aged Hakkaisan “Yukimuro,” are poured by informative servers as part of a pairing option. An la carte menu is available in tandem, with hand rolls, sashimi spreads, and creative plates like wagyu “toast” atop brioche, lobster tempura, foie gras crudo, and miso-mochi churros. The vibe Encounter a 40-seat setup decked out in zippy neon light and swirling ocean murals reminiscent of the famous Great Wave art series of Mount Fuji. A DJ booth comes to life in the back on weekends. Insider tip Kim does double duty at the sleek hotel as head of the lobby-level sushi and omakase room, Wren. ...read more read less