Macau was a Portuguese Colony right next door to Hong Kong. Why didn't Japan invade it during WW2?
Japan did invade Hong Kong, and they did invade Portuguese Timor too. Yet I am not even sure if Japan ever declared war on Portugal.
Other colonies they invaded were French Indochina, British Burma, American Phillipines, Dutch Indonesia. I may have missed some, but Macau is very obviously standing out here.
The Japanese were ostensibly very anti-colonial and proselytized their Greater East Asia Co-Prosperity Sphere, and Macau is a very obvious colony right in range of them.
Wikipedia has this to say about it:
In August 1943, Japanese troops seized the British steamer Sian in Macau and killed about 20 guards. The next month they demanded the installation of Japanese "advisors" under the threat of overt military occupation. The result was that a virtual Japanese protectorate was created over Macau.
I don't know if that counts as an invasion, but I'm inclined to think not. It sounds similar to the situation in Vietnam where first Japan stationed troops there with Vichy French consent, which I have never heard described as an invasion. (Later, Japan moved in a much larger force without permission, and this has been described as invasion.) In any case, what did these "advisors" do or enforce in Macau, if anything? Did these "advisors" see any combat?