San Francisco's defining speakeasy since 2006 — an unmarked Tenderloin door, a password, dim rooms with original 1920s tin ceilings and exposed brick, and a cocktail program that takes Prohibition-era classics as seriously as the room's history demands. House rules: no cell phones, no standing at the bar, no shouting. The drinks land somewhere between meticulous and generous. The kind of bar that started a national speakeasy revival and still does it better than most of its imitators.