150 pillboxes and counting: locating Hong Kong's pre-WWII military emplacements

Pillboxes, in military terms, are concrete emplacements with small openings from where guns are fired. By the time of Japanese invasion of Hong Kong, the British had built a series of pillboxes stretching from Kwai Chung in the west to Port Shelter, Sai Kung in the east to form what is known as the Gin Drinker’s Line, to protect the Kowloon Peninsula from enemies advancing from the New Territories.