Why did the Japanese invade Macao only during World War II?

People in China always move to another place. These harsh conditions are tantamount to uprooting them and completely cutting off their ties with the motherland. Of course, nobody wants to go. The rulers of the Qing dynasty were dissatisfied with these cooperation conditions, so they were too lazy to take a reason.

Seeing that China was not very enthusiastic about this, the Portuguese colonists had to consult with Japan, which had a small area and a large population. The Japanese were overjoyed and immediately agreed to export a large number of laborers to Brazil. By the beginning of World War II, more than 3 million Japanese had emigrated to Brazil.

Faced with Japan's wanton aggression in World War II, Portuguese colonists were very nervous and worried that Japan would invade Macao, so they asked Brazil to send a note to Japan, which wrote: "If the Japanese invade Macao by force, Brazil will expel all Japanese overseas Chinese to their own countries."

This deterrent really worked, and the Japanese broke out in a cold sweat. If 3 million people are swept out of the house together and rushed back to their hometown of Japan, it will not only cause great confusion, but also bring a lot of trouble. Therefore, the Japanese, eager to get out of trouble, succumbed to pressure and dared not attack Macao from beginning to end in World War II.