A night at Zenkichi can feel like a scene out of a 1940s paperback mystery. There's no sign on the wood-paneled exterior, just a light over the door, and a pretty hostess working the rope guards the stairs to the dining room. Inside lies a twisting maze of dark-wood booths that resemble private dining cars on a train. Billyburg couples can get cozy by closing the blinds, their only connection to the outside world a call button to summon the waitress. The setting may sound gimmicky, but the elegant, small Japanese plates are deadly serious--and seriously delicious.