The entrance to Yorozuya Okagesan is, to put it mildly, discreet. The modest sign is set back so far from the sidewalk you'd never spot the steps unless you knew to look. And you'd never go down them anyway unless you had a reservation since, politely but inevitably, you would be turned away.

Don't get the wrong idea. Okagesan is not some uber-exclusive, introductions-only club. Far from it. This friendly, bustling izakaya just happens to be so popular — and booked out almost every day of the year — it has no need to attract casual walk-in customers.

At first glance, it's hard to understand why. Peer through the doorway into Okagesan's compact basement premises and it seems little different from hundreds of other old-school taverns that dot the city's numerous nightlife neighborhoods. But once you have spent an evening there, you start to appreciate what makes it special.