I’m here to learn...by whom, when and why?
The peace side decided to counteract the martial effect of that news release with an announcement of their own. This was for several reasons. The government sponsored news agency was in Morse code only and not covered by military censorship; it would speed the receipt of the Japanese offer going through diplomatic channels and could possibly postpone destruction of another city; and it was hoped that rejoicing created among the allies by an end to the war would make them unable to reject Japan's counter offer. On the morning of the 11th, the army was furious, but did not resort to violence. That evening the Emperor agreed to broadcast to the nation on acceptance of the offer.
The stern Allied response, written by the Americans and approved by the Allies, was also released by radio news to let Japan know under what terms the agreement was accepted. It was received about midnight August 11-12, eighteen hours before the diplomatic note. As word spread within the government, about midnight of the 13th, a plea was made to commit twenty million lives (kamikaze) to victory. On the morning of the 14th Allied leaflets erased the secrecy of the negotiations. Noon on the 14th saw another imperial conference in which the three military leaders in the cabinet spoke for rejection. The Emperor considered the Allied response to be acceptable. The cabinet met immediately after and endorsed the Emperor's wishes, thereby making the acceptance legal. By three in the afternoon, the government Morse code station announced that an "acceptance will be forthcoming soon." The Allies stopped attacks and went on alert status.
Insurgents assassinated the commander of the Imperial Guards and issued orders under his name, but the insurrection was put down by morning. Separately, the War Minister committed suicide. Also overnight, the Emperor recorded his address to the nation which was broadcast at noon, 15 August. Wording was so carefully drafted, about saving innocent lives from a new and cruel bomb, that it was not immediately known that it meant full surrender. The cabinet resigned as a duty and an Imperial Prince was made premier.
Excerpt from entry for Surrender of Japan
Late on the night of August 12, 1945, Major Kenji Hatanaka, along with Lieutenant Colonels Masataka Ida, Masahiko Takeshita, and Inaba Masao, and Colonel Okitsugu Arao, the Chief of the Military Affairs Section, spoke to War Minister Anami Korechika, hoping for his support, and asking him to do whatever he could to prevent acceptance of the Potsdam Declaration. General Anami refused to say whether he would help the young officers in treason. As much as they needed his support, Hatanaka and the other rebels decided they had no choice but to continue planning and to pull off the coup on their own.
Hatanaka spent much of August 13 and the morning of August 14 gathering allies, seeking support from the higher-ups in the Ministry, and perfecting his plot. Around 21:30 on August 14, Hatanaka's rebels set their plan into motion. The Second Regiment of the First Imperial Guards had entered the palace grounds, doubling the strength of the battalion already stationed there, presumably to provide extra protection against Hatanaka's rebellion. However, Hatanaka, along with Lt. Col. Jirō Shiizaki, convinced the commander of the 2nd Regiment of the First Imperial Guards, Colonel Haga Toyojiro, of their cause, and (untruthfully) that the War Minister, Army Chief of Staff, and the commanders of the Eastern District Army and Imperial Guards Divisions were all in on the plan.
Originally, Hatanaka hoped that by simply occupying the palace, by simply showing the beginnings of a rebellion, the rest of the Army would be inspired and would rise up against the move to surrender. This philosophy guided him through much of the last days and hours and gave him the blind optimism to move ahead with the plan, despite having little support from his superiors. Having set all the pieces into position, Hatanaka and his co-conspirators decided that the Guard would take over the palace at 02:00. The hours until then were spent in continued attempts to convince their superiors in the Army to join the 'coup'. At about the same time, General Anami committed seppuku, leaving a message that, "I — with my death — humbly apologize to the Emperor for the great crime." Whether the crime involved losing the war, or the coup, remains unclear.
At some time after 01:00, Hatanaka killed Lt. General Takeshi Mori, Commander of the 1st Imperial Guards Division, when Mori refused to side with him. Hatanaka feared that Mori would order the Guards to stop the rebellion. Lt. Col. Shiizaki and Captain Shigetaro Uehara of the Air Force Academy were also present in the room, and Uehara is presumed to have killed Lt. Col. Michinori Shiraishi, Staff Officer of the 2nd General Army. These were the only two murders of the night. Hatanaka then used General Mori's official stamp to authorize Strategic Order No. 584, a false set of orders created by his co-conspirators, which would greatly increase the strength of the forces occupying the Imperial Palace and Imperial House Ministry, and "protecting" the Emperor. The Palace police were disarmed and all the entrances blocked; but as of yet, no one in the Imperial House Ministry was aware of what was transpiring. Over the course of the night, Hatanaka's rebels captured and detained eighteen people, including Ministry staff, and NHK workers sent to record the surrender speech.
The rebels, led by Hatanaka, spent the next several hours searching for the Imperial House Minister, the Lord of the Privy Seal, and the recordings of the surrender speech. They never found the recordings, which were hidden among pieces of bedding in an emergency cupboard. The search was made more difficult by a blackout, caused by Allied bombings, and by the archaic organization and layout of the Imperial House Ministry. Many of the rooms' names were unrecognizable to the rebels. During their search, the rebels cut nearly all of the telephone wires, severing communications between their prisoners on the Palace Grounds and the outside world.
Around 03:00, Hatanaka was informed by Lt Col Ida that the Eastern District Army was on its way to the Palace to stop him, and that he should simply give up. Finally, seeing his plan crumbling to pieces around him, Hatanaka tried to plead with the Chief of Staff of the Eastern District Army to be given at least ten minutes on the air (on NHK radio), to explain to the people of Japan what he was trying to accomplish and why. He was refused. Colonel Haga, commander of the 2nd Regiment of the First Imperial Guards, discovered that the Army was not, in fact, in support of this rebellion, and he ordered Hatanaka to leave the Palace Grounds.
Just before 05:00, as his rebellion continued its search, Major Hatanaka went to NHK studios, and, brandishing a pistol, tried desperately to get some airtime to explain his actions. A little over an hour later, after receiving a phone call from the Eastern District Army, Hatanaka finally gave up. He gathered his officers and walked out of the NHK studio.
By 08:00, the rebellion was entirely dismantled, having succeeded in holding the Palace Grounds for much of the night but ultimately failing to find the recordings. Hatanaka, on a motorcycle, and Lt. Col. Shiizaki on horseback, rode through the streets, tossing leaflets that explained their motives and their actions.
Within an hour before the Emperor's broadcast, sometime around 11:00, August 15, Major Hatanaka placed his pistol to his forehead, and pulled the trigger. In his pocket was found his death poem: "I have nothing to regret now that the dark clouds have disappeared from the reign of the Emperor."