In fact, the reason why Roosevelt suddenly imposed a material embargo on Japan was another external opportunity, that is, the Chinese government, under the repeated advice of German advisers, finally made up its mind to declare war on Japan.

That's right, after all, Germany did not have a mandatory recall of advisers, so the German military advisory group that went to China at the beginning actually stayed in China all along, but many members were changed during the period, but the organization is still there.

Although it was almost the same as the original historical declaration of war, and it had no impact on the historical course of China's War of Resistance Against Japanese Aggression, it was the declaration of war that was issued after all.

And this time, the news of China's declaration of war on Japan undoubtedly provided Roosevelt with a good excuse to block the export of oil and other strategic materials to Japan.

After all, after the outbreak of the Sino-Japanese War, the United States has always adopted a policy of non-intervention and avoidance of involvement. However, since China and Japan did not declare war, the United States did not impose an indiscriminate embargo on China and Japan, but only forbade US merchant ships from transporting arms and other military supplies to these two countries, and did not impose restrictions on the rest of the goods.

However, this US policy is obviously beneficial to Japan and detrimental to China, because Japan has the ability to blockade China's coastline, while China does not have the ability to blockade Japan's coastline.

In fact, after occupying Northeast China and Korea, Japan was very helpless to find that they could not find enough resources to stimulate their own industrial economy.

In addition to the steel and coal mines that Japan urgently needs in the three eastern provinces, the remaining rubber also has oil resources, and in fact Japan still has to ask the US imperialists to export to them.

Moreover, it is inconvenient for the United States to import these materials into Japan, which is still seriously related to Japan's lifeblood.

At that time, Japan's national strength could no longer support the attrition caused by large-scale offensive warfare, and its claim to be the third navy in the world (in fact, it should have been ranked fourth, and Germany really became the third after beating the British navy down), could not support the army in the battle at all.

Of course, the Japanese Navy was not very willing to bother with the merits of the Army.

Many people think that the reason why China was able to win the war against Japan was basically all because of the war between the United States and Japan. Such a statement is actually unfair.

Originally, the dog-eat-dog between the United States and Japan in history did relieve a lot of pressure on China, but in fact, as long as the Chinese army continues to work hard, the Japanese will become more and more unsustainable and slow down their offensive in the land of China because of the supply problem alone. This situation was very similar to the situation in the First Sino-Japanese War, when the Manchu government had survived the destruction of the Weihaiwei Beiyang Naval Division and the defeat on the Korean battlefield, and with the national strength of Japan at that time, it would not have been able to continue fighting.

Fortunately, in World War II, the Chinese were competitive enough, and even if the capital fell, they continued to fight with the Japanese army until the last moment!

And now, the Chinese side is surprised to find that it seems to be more and more capable of fighting, and it may be that the Japanese army is going downhill more and more. In short, China was so aggressive that after the arrival of 1941, it declared war on the Japanese government.

"I hereby formally declare war on Japan, and declare to China and foreign countries that all treaties, agreements, and contracts involving relations between China and Japan shall be abolished, and it is hereby announced!"

Under a declaration of war, the Chinese side took the strongest stance and responded directly to the Japanese invasion.

So, some people may wonder why China declared war on Japan after so many years of war.

In fact, a large part of the reason for this is that the Chinese side is worried that the equipment of the German mechanic may be lost.

Before the outbreak of the Anti-Japanese War, China, with the help of the German military advisory group, had already trained and equipped four standard German armament divisions, but by the time China and Japan started fighting, there were still a large number of scheduled equipment that had not arrived. Because in the original plan, there were more than four German mechanics to be expanded in China.

Fearing that the Japanese army would impose a naval blockade and prevent supplies from the German side from coming in, China did not declare war for a long time.

Interestingly, China believes that declaring war on Japan will do more harm than good, but Japan also believes that declaring war on China will do more harm than good.

After all, Japan has installed a puppet Nanjing government, so it will not be able to declare war on the Nationalist government in Chongqing. Because that would be tantamount to admitting that the puppet Nanjing government supported by Japan is not the real government of China.

Thus, a miracle in the history of war appeared: China and Japan were in a state of war until China declared war on Japan. But at the same time, the diplomats talked, and the soldiers did the same. Talking is a real talk, and fighting is also a real fight, and there is no delay between the two.

The reason why the Sino-Japanese War has continued to be fought until now and has not ended, and it can still give China time to declare war, is that there is basically no mechanized combat in the standard sense on the battlefield in China.

For the Chinese and Japanese armies, the concept of mechanized warfare is too far away. Although the Japanese army has a lot of tanks and armored vehicles, it is not up to par in terms of technology and theory, and in addition, the oil is also very tight by the United States, and the reserves are not much, so it does not have sufficient capital to launch mechanized operations.

China's performance in this area was even worse, at the beginning of the war there was only one regiment of armored troops, and its main equipment was still the "Fiat" light tanks provided by the former Italian leader Benito Mussolini, which had proven to be waste in East and North Africa against the forces of the British Commonwealth - and had also been used by the Chinese army in the previous Battle of Songhu with two companies, which had been largely lost and of little use.

For many reasons, even if the Japanese army played pure infantry battles on the battlefield in China, plus all kinds of battles of wits and courage with guerrilla warfare and tunnel warfare, not to mention the slow progress, it was still quite tired when it came in.

As a result, the Japanese army base camp, which found that it did not have many strategic reserves in its hands and was still stuck by the United States, finally made up its mind to open the knife in a different direction.

Needless to say, the previous trip to the north made the Japanese army suffer, and the army is really not easy to clamore for another north.

Although a small number of northbound factions still fantasize about joining the German army with the Soviet Union, the attitude of other Germans has always been very cold, which makes these people put their hot faces on their cold butts, which is very embarrassing.

Now, the navy-dominated southbound faction suddenly proposed to take advantage of the historical opportunity of Britain being pressed to the ground by the German army, coupled with the lax state of the United States not yet participating in the war, to take over Southeast Asia, which was originally within the scope of British and American strength, in one fell swoop.

As soon as this remark came out, coupled with the recent appearance of garbage and waste wood by the British, it made many people very excited.

On the other hand, Japan is rampant and has no intention of landing on the US mainland. From the very beginning, they simply worked out a strategic defense system that attacked first, played superiority and then defended.

As for the resources that Japan needs, they don't have to go to the United States to grab them. To the Philippines and Myanmar, which are Southeast Asian regions, there are not only oil resources that can be exploited, but also rich rubber resources that can be utilized, and taking them down can just make up for Japan's shortcomings.

It was at this time that a piece of information about the lax combat readiness of Pearl Harbor was sent to the Japanese base camp......