On December 8, 1941, Japan attacked Pearl Harbor and immediately attacked Hong Kong and Singapore, but did not hurt the close proximity of Macao. The ostensible reason was that Japan had not declared war with Portugal and that there was no state of war, indicating that Japan "scrupulously complied with" public international law. It's all nonsense, of course.

As a matter of fact, if the Japanese wanted to occupy Macao, it could be said that it would be effortless, and they would solve the problem without firing a single shot. So there are strategic reasons for not doing so.

Macau was too small, less than 20 square kilometers at the time. Although there are coasts on three sides, they are blocked by the sediment washed down by the mouth of the Pearl River, and even 1,000-ton ships cannot dock. Since the Opium War, Hong Kong's maritime superiority has been taken over, and Macao's trade economy has long plummeted.

Macao, which is a small projectile land, has neither a deep-water port nor an aviation airport, and has no strategic significance, so what is the use of the Japanese coming? It is too uneconomical for Japan to tear the skin of Portugal for this useless place.

Hong Kong was originally the largest international intelligence market in the East. The Japanese estimate that after the fall of Hong Kong, a large number of intelligence and espionage personnel will concentrate on the Macao Peninsula to form a new intelligence center, and this is also one of the reasons why Japan will not invade and occupy Macao.

However, because Macao's land and sea communications were cut off, spies could not operate, and the Japanese wish was never realized. Lisbon, the capital of Portugal in Europe, is truly an international intelligence center. Hitler deliberately kept it and let the "fifth column" run wild. Japanese spies were also particularly active, where they obtained a large amount of intelligence material about the Soviet Union and Anglo-Americans. If a small and useless Macao was captured in the East, Japanese intelligence officers would be expelled from Lisbon. Naturally, the Japanese would not do such a loss-making transaction.

There was another important reason why the Japanese did not dare to occupy Macao. Since the 15th century, Portugal has had a large number of colonies in Africa and South America, and Brazil is one of them. Brazil is a vast and sparsely populated country, and Portugal initially asked the Qing government to approve immigration for reclamation, but was refused. Later, he turned to Japan to plead, and Japan and Portugal reached an agreement, and a large number of Japanese emigrated to Brazil. By 1945, there were 3 million Japanese nationals in Brazil.

Since the Meiji Restoration, Japan has been sending planned immigrants to foreign countries in large numbers, and the Japanese military has great ambitions, arranging long-term hidden and lurking spies among the immigrants, who will be passed down from generation to generation to collect intelligence and be loyal to the emperor. In the Pearl Harbor incident, the Japanese diaspora in Hawaii played such a role.

Since the outbreak of the Pacific War, it is said that the Portuguese government has informed Japan that if the Japanese army invades and occupies Macao, all Japanese expatriates in Brazil will be imprisoned in concentration camps. In this way, Japan will lose a huge source of intelligence from the United States and South America. The Japanese are not fools, so naturally they will not occupy Macao.

For these reasons, Japan did not occupy Macao during World War II. But despite the lack of occupation, Macau remained under the tight control of the Japanese.