According to the spirit of the 1943 Cairo Declaration, the United States, Britain, and China agreed to the purpose of "carrying out the war against Japan to the end until Japan's unconditional surrender." Subsequently, the draft of the Cairo Declaration was sent to Tehran, and the Soviet Union also expressed its approval. This indicates that the United States, Britain, China, and the Soviet Union have formed a division of interests in the war against Japan, and have also initially established a program of action.
At this time, the situation in the Second World War was not so clear, the German fascists were still fighting back desperately, and the Japanese army in the Pacific was also resisting extremely fiercely, so the countries did not contradict this declaration of mutual assistance, but on the contrary hoped to get help from it as soon as possible.
So, when the final moments of 1945 came, the Japanese actually faced a very sad prospect that they had been torn apart and divided on the allied strategic drawings, and the Allies had not only planned the mission of fighting against Japan, but also carried out the post-war division occupation, and Japan faced more than just the pressure of the United States.
In fact, Japan before the atomic bomb explosion could not support itself, and the US military, out of the consideration of competing for strategic interests, very much hoped that Japan would surrender as soon as possible, so that they could leave more troops and national strength for the post-war struggle for hegemony, and also curb the expansion of the Soviet Union in the Far East to the greatest extent. So they were quite eager to use almost all means against Japan, such as super-large-scale incendiary bombings, blockades, destruction of Japanese agriculture and people's livelihood, and even the use of biological attacks such as locusts.
On the one hand, the Emperor is unwilling to abdicate, and secondly, the Japanese believe that they have grasped the key points of the Allies, and they perceive that the Rift between the United States and the Soviet Union has been opening, and even the Rift between the United States and Britain, the Rift between the Soviet Union and the United States, the Rift between France and the United States, which involves the redividing of interests after the war, so the Japanese have an illusion that the rift between the Allies is their own life-saving straw.
This kind of cognition made the weakened Japan strongly reject the Potsdam Proclamation, although there was no food to eat, no drink to drink, not enough weapons, the people could only be fooled into going up to fight with bamboo poles, but the Japanese government and the emperor were still unwilling to admit their fate, they stepped up their efforts to start diplomacy on the Soviet side, hoping that the Soviet Union could "mediate", and even did not hesitate to trade part of the occupied land with the Soviet Union.
However, the Soviet Union was not willing to risk the world's great disobedience, and Japan could not stand it, and it was a fool not to fish at this time. So they stopped continuing to cooperate with Japan, and Several major generals, including Vasilevsky, were secretly mobilized to the Far East and began to brew a war against Japan, and Japan's "good offices" document for the Soviet Union was also handed to the White House.
It was not surprising that the Soviet Union did this, at that time Japan did not have the slightest ability to resist, although the Japanese government boasted of "100 million people jade fragments" and relied on Ushijima Man and other generals in Okinawa to achieve high killing records against the US army, but Japan was indeed a sick man who fell at a touch, and the Allies were only worried about the number of casualties and the benefits they had gained.
In fact, the Japanese government at that time was always looking for a step to end, but they did not find a good opportunity. The first is that the emperor is unwilling, and for him, the survival of the emperor system is the first important thing. For this reason, Emperor Hirohito walked with senior officers of the Army faction, such as Anan, who, as the most die-hard member of Japanese militarism, would rather die than be caught and tried.
On the contrary, the naval red deer before the end of the war was quite eager to surrender, and when Koiso Kuniaki was ousted from power, the naval faction's Suzuki Kantaro immediately came to power, he was actually the glove of the former prime minister, the navy lord and the faction leader Mitsumasa Minouchi, and the gang was quite eager to contact the Allies and surrender as soon as possible.
The atomic bomb also played a role at this time, it found a good opportunity for Japan to step down, and the Japanese emperor also got a promise that "the US military is willing to temporarily not ban the national system", so he immediately kicked away the main war faction such as Anan and turned to firmly support the main peace faction of Michi Mitsumasa. To this end, Japan also launched a coup d'état on the eve of its surrender, but unfortunately it did not succeed in the end.
Therefore, we really do not have to think too much about the Japanese resistance forces, after experiencing the great wars of Iwo Jima, Okinawa, etc., the scorched earth of Japan is not much stronger than after the atomic bombing, they simply do not have the ability to fight with multiple allies, the United States, Britain, China, and the Soviet Union rushed up, and Japan can resist for a month.
According to the behavior of the emperor and others before the end of the war, they had long been prepared to surrender, and they had bargained, but what was missing was the steps. It didn't matter if there was an atomic bomb at this time, they were just waiting for the ladder built by the Allies with a big move, and they could kneel and beg in an instant.