The chef’s counter at Sushi Yūgen is an eight-seat oasis at the rear of the main restaurant, where Kyohei Igarashi serves his omakase menu of 20-odd courses twice nightly. Bookings here are hard to come by. If you’re looking to understand why, consider his truffle season specialty: In a domed bowl sculpted entirely from ice, three plump slices of shiromi are fanned out in a pool of truffle sauce beneath fresh truffle shavings and glittering gold leaf — an exquisite pairing. Another signature dish features sliced steamed Japanese abalone in a sauce of its own puréed liver. Other offerings might include thin noodles (sōmen) in chilled dashi, a madai shabu-shabu. The sushi is ultra-seasonal and like the vegetables and everything else served here (except for truffles and caviar) is sourced from Japan. Igarashi’s cuisine is distinct from the expected, rigid orthodoxy of a well-trained itamae. It reflects his training in both Michelin-starred sushi restaurants and kaiseki — and his desire to bring together the best of both worlds, along with a taste of his travels. It works. The room, meanwhile, is spare and elegant. The seasonally attuned sake list is impressive and building constantly, with a slew of private imports, some unavailable elsewhere.