The 2,000-pound second world war bomb that brought chaos to Happy Valley was dropped during a huge one-day pounding of Japanese positions in the city in 1945, US military documents have revealed.
As the hundreds evacuated on Thursday from hotels, offices and flats near the construction site where the bomb was unearthed returned yesterday, amateur military historian Craig Mitchell said it was likely that the ANM66 was one of just 11 bombs of such size and destructive power ever dropped on Hong Kong during the second world war. The raid took place on January 16, 1945.
Police records show that the device was only the second of its kind found in the city since the end of the war.
Mitchell, who has spent years researching the legacy of Hong Kong's wartime past, said the bombers in the January 16 raid came under fierce anti-aircraft fire and attack by fighter planes, which might explain why the bomb landed wide of its target - Taikoo Dockyard. He said there were 12 US aircraft carriers close to Hong Kong at that time, but only two carried that type of bomb.
On that day, two TBM- Avenger bombers carried the payload of 11 2,000-pound bombs over the city. Four were dropped on Taikoo Dockyard, another on Aberdeen docks and one on Kowloon docks, according to US military documents provided by Mitchell. The other five targeted ships.
One narrative on the Taikoo docks attack in the documents said: "Five planes dove [sic] from south to north, releasing their bombs between 3,000 and 3,500 feet, and all bombs were observed to hit in the dry dock area ... It is considered that serious damage was done to these ships, as well as to the dry docks themselves."
Hundreds of other smaller bombs were dropped on Hong Kong on the same day.
Mitchell said the bomb probably hit Happy Valley because the bomber had strayed off course.
"The planes were releasing the bombs at 3,000 to 3,500 feet under very, very heavy anti- aircraft fire so there was lots of chaos," he said. "It appears roughly between the two targets of Taikoo docks and the navy boatyard in Tamar."
The other ANM66 bomb found in the city was discovered by Mitchell in Tai Tam Country Park last year. He said it was unusual because the explosives inside were removed.
Mitchell estimates that between 25 and 30 per cent of the bombs dropped on Hong Kong during the second world war failed to detonate. While more unexploded ordnance could be in Happy Valley, it was unlikely any other device of that size would be found in the area.
Albert Lam Ping-wai, of the Ex-Servicemen's Association, said 35 to 40 per cent of the bombs dropped from a plane would miss their target. The bomb found in Happy Valley could have hit soft soil and its thick shell could have made it more difficult to go off.
Lam said Happy Valley had its own significance during wartime, as a Japanese military camp was located on Morrison Hill.