We all know about the atrocities that the Japanese committed in China, but if they had a stranglehold on the Chinese, what happened to Hong Kong, which was still a British Colony at that time? I know about the fighting between the British and Japanese in Singapore and India, but did the British actually fight the Japanese in Hong Kong or any of mainland China?
On the 25th of December, 1941, the British Crown Colony of Hong Kong surrendered to the Empire of Japan. The short battle – less than 20 days – ended in a disastrous defeat for Hong Kong and those who fought on its side. The primitive attempts at defending Hong Kong were a complete failure; parts of Hong Kong fell to the Japanese in as quickly as five days, with several subsequent skirmishes which eventually led to the surrender of the British Colony.
It was well known even before the battle took place that Hong Kong simply could not be defended. It was difficult to defend because it was a sea port; the borders were extremely easy to cross and this was shown how in 1941 people could cross the border with ease. The British, on the other hand, were experiencing something close to cognitive dissonance. They knew that Hong Kong must be defended, if not for its strategic and geographical importance, then for its message to the Japanese that fascism and brutish expansionism would not be tolerated. But at the same time, the British knew that defending Hong Kong would be virtually impossible. Many historians argue that one of the reasons the Battle for Hong Kong was such a failure and lasted such a short time was because the British did not trust the non-European community. This distrust meant that those who did want to help the British repel the Japanese were ostracized and unable to be utilized. Whether the Chinese could be admitted into British regiments was already a controversial topic, and the British remained obstinate. This was also partly to do with the fact that the British did not want to work with China until the Japanese actually attacked, and were suspicious of the Nationalist leader Chiang Kai-shek’s motives for wanting to help Hong Kong. Chiang and China may have changed their outlook of Hong Kong, and historian Chan Lau Kit-ching points out that Hong Kong’s new importance as China’s only remaining port may have put emphasis on Hong Kong as a city of rising importance. Hong Kong’s importance as a port was not new. Before the Japanese invasion, Hong Kong was the only port exempt from Japanese control, and supplies were being sent through Hong Kong to supply the anti-Japanese war effort in China. This brought Hong Kong’s geographical importance to the attention of the Japanese, and later to the British and the United States.
As for atrocities committed in mainland China, since the majority of Hong Kong's population was ethnic Chinese, Japanese treatment of Hong Kong residents remained by and large the same as those treated on the mainland, with the exception of deathcamps like Unit 731. There was also a larger population of Japanese sympathisers and those who worked with the Japanese for business-related purposes.
See John Carroll's A Concise History of Hong Kong.
Yes they did. The Japanese attacked Hong Kong without declaring war and easily outnumbered the British, Canadian and Indian troops stationed there. The British troops stationed were ill-prepared and had little air and naval support, with their airport being bombed. (1)
As for mainland China, it was rather limited. The British and Australians started a secret mission to train the Chinese army to fight back against the Japanese and they were stationed largely in Burma. Towards the end of the war, the British were directly involved by providing medical and explosive experts to the conflict. (2)