Like a scene out of a Hong Kong triad movie, the mahjong parlour in Temple Street is filled with cigarette smoke, the incessant click-clack of tiles and the grim, hard faces of gamblers.
On a prominent altar for Guan Gong, the righteous Taoist God of War, lies a giant bundle of ginger, shaped like a hand. A knife is stabbed through it - an ominous warning, it seems, for anyone contemplating cheating at the tables.
The manager of Hong Kong's oldest mahjong parlour Kai Kee Mahjong laughs it off. "It's just to create sat hei, a menacing atmosphere, which brings good fortune to our business," says Mr Devil Yau - his real name, he insists.
Filled with mystique, rituals and superstitions - including the famous one about wearing red underwear for luck - playing mahjong has long been a way of life for Hong Kongers.
And it has been posited that the game is a possible factor for why they are among the longest-living people in the world. Last year, the city's men and women came in second in terms of longevity after Japan, living to ages 81 and 86.3 respectively.
Various studies have documented the health benefits of mahjong, due to the need for a player to calculate points and remember the rules and tiles already thrown out, as well as for its social interactivity. Three or four players are needed to form a table for a game.
In a study published this year, the Hong Kong Institute of Education found that regular mahjong playing and taiji practice among nursing home residents slow down cognitive decline even for those suffering from dementia, as compared with those engaged in handicraft activities.
"Mahjong kept them mentally active through participation in a leisure activity that is enjoyable and mood-lifting," says Professor Cheng Sheung Tak, a psychology and gerontology academic who led the research.