Then & now: open secrets

Widespread public concerns have arisen in recent years about official hacking of private information. Unsettling revelations about personal-data storage emerged during the WikiLeaks scandals and erupted again after the American National Security Agency whistleblower Edward Snowden surfaced in Hong Kong.

Very little personal information requires a serious search to find these days; the sheer volume of online incontinence spawned by Facebook, Twitter, WhatsApp and so on offers an embarrassment of freely divulged information to metadata miners, whether official, commercial or - as increasingly seems to be the case - an unholy nexus of both.

But how was information-gathering, dissemination and general surveillance done in the past? Seventy-two years ago in Hong Kong, at about 4.45am on December 8, 1941, Major Charles Boxer, the British intelligence chief, was listening to the Japanese radio news, broadcast on short wave from Tokyo. Inserted into the weather bulletin was a brief and, on the surface innocuous, sentence - " Higashi no kaze ame" ("East wind, rain") - a coded signal for Japanese forces poised across East Asia to attack.

Other codes slated for inclusion according to need were " Kitano kaze kumori" ("North wind, cloudy"), which signified a diplomatic break with the Soviet Union, and " Nishi no kaze hare" ("West wind, clear"), which indicated a Thai diplomatic break with Britain and a pre-emptive invasion of Thailand by Japanese forces. It went out, as they say in the trade, en clair ("in clear"). Hidden in plain sight, the Pacific war had begun. Then as now, the most secretive acts are orchestrated in the public gaze, in broad daylight.

Half an hour after Boxer relayed the message to China Command headquarters, Japanese forces crossed the frontier from Shum Chun (Shenzhen) and, three hours later, bombers flew down from Canton (Guangzhou) to bomb Kai Tak airfield. As far as Hong Kong was concerned, the war had started.

Across the Pacific, Hawaii's Pearl Harbor had already been attacked, troop landings in Malaya were imminent, and Singapore and the American airfields in the Philippines were bombed.