It was customary that a Prime Minister and his cabinet would resign if they felt they had failed the Emperor. From 1943 onward, the failures in the execution of the war were happening fairly regularly which led to a fair amount of turnover.

The Tojo cabinet resigned after the fall of Saipan. The entire Japanese strategy for the war had revolved around early victories and then creating a defensive ring of islands to protect those gains. This ring had been steadily tightening through Nimitz' island hopping and MacArthur's Australians and Americans advancing up the coast of Papua New Guinea. The fall of Saipan and Tinian in the Marianas meant that Allied bombers would now be able to strike the Japanese home islands, which led to Tojo's resignation.

Tojo was replaced by Kuniaki Koiso as Prime Minister on July 22, 1944. The new war plan put forward to the Emperor was to have a great battle in the Philippines that would be so costly for the Allies that they would sue for peace under favorable terms. However, the plan was poorly planned, poorly executed, and poorly communicated to the Philippine commanders and throughout the army. The Philippines were taken, and in April, 1945 Koiso resigned after the allied invasion of Okinawa.

Koiso was replaced by Kantaro Suzuki, who the emperor and Lord Privy Seal Marquis Koichi Kido hoped could arrange some sort of surrender that would be acceptable to both the Allies and the Japanese military. Suzuki and his cabinet resigned on August 17th after finally signing off on acceptance of the Potsdam declaration by order of the Emperor.

Suzuki was replaced by Prince Naruhiko Higashikuni who was tasked by the Emperor to sign the actual terms of surrender. Higashikuni, a member of the royal family and officer of the Imperial Japanese Army, resigned along with his cabinet after MacArthur as Supreme Commander for the Allied Powers ordered the dissolution of the Peace Preservation Law of 1925, the abolishment of the Tokko or "Thought Police", and the release of political prisoners, including many communists. This order was unthinkable for Higashikuni who resigned and was replaced by Kijuro Shidehara in October.

Basically the various governments resigned for different reasons, but it was all due to the rapidly changing situation for Japan in the war and eventually at home.