The Thirtieth of September Movement (Indonesian: Gerakan 30 September, also known as G30S, and by the syllabic abbreviation Gestapu for Gerakan September Tiga Puluh, Thirtieth of September Movement, also unofficially called Gestok, for Gerakan Satu Oktober, or First of October Movement) was a coup movement allegedly orchestrated by the leaders of the Communist Party of Indonesia (PKI) and its sympathizers within the Indonesian military.
In the early hours of 1 October 1965 in Jakarta, G30S assassinated six Indonesian Army generals, including the Commander of the Army Ahmad Yani, in an abortive coup d'état. The Coordinating Minister for Defense and Security, General Abdul Haris Nasution, survived the assassination attempt in his house after being urged to escape by his wife, and he jumped into the residence of the Iraqi ambassador next door. But his lieutenant Pierre Tendean was killed while trying to protect the general by claiming he was Nasution. Ade Irma Suryani, Nasution's daughter, was also shot during the chaos and died a few days later.
Later that morning, the organization declared that it was in control of media and communication outlets and claimed to have taken President Sukarno under its protection. During that chaotic morning, Sukarno decided to go to Halim Perdana Kusuma Airport, and eventually rejected giving his support to G30S. Meanwhile Suharto, alongside Nasution and other military officials, managed to suppress G30S in Jakarta. By the end of the day, the coup attempt had failed in the nation's capital. The leader of PKI, D.N. Aidit, who was also at Halim Airport during the coup attempt, decided to escape to Yogyakarta on 2 October 1965.
The bodies of the slain military officers in Jakarta were thrown into a well in Lubang Buaya, near Halim Airport. Suharto was involved in the evacuation process of the bodies on 4 October. The funeral procession for the seven military officers, known as Pahlawan Revolusi (Heroes of the Revolution), was held on 5 October 1965. At that time, Kompas described the funeral as being witnessed by a sea of people in Jakarta. Sukarno was notably absent from the funeral.
In the days and weeks that followed, the army, socio-political, and religious groups blamed the coup attempt on the Communist Party of Indonesia (PKI). Soon a mass purge was underway, resulting in the imprisonment and deaths of many actual or suspected Communist Party members and sympathizers. According to most estimates, at least between 500,000 to 1 million people were killed, with higher estimates reaching 2 to 3 million.
Investigations and questioning of Suharto's version of the events were long obstructed in Indonesia. While the Central Intelligence Agency (CIA) initially believed that Sukarno orchestrated the entire coup, several outside sources found inconsistencies and holes in Indonesian army claims, notably Benedict Anderson and Ruth McVey, who wrote the Cornell Paper that challenged it.
Background
From the late 1950s, President Sukarno's position depended on balancing the opposing and increasingly hostile forces of the army and the PKI. His "anti-imperialist" ideology made Indonesia increasingly dependent on the Soviet Union and particularly China.
In the 1960s, the conflict between the army and the PKI intensified when the PKI asked President Sukarno to support the establishment of a Angkatan kelima, a left-wing militia of workers and peasants armed primarily to support the ongoing confrontation with Malaysia. This proposal was opposed by the army generals of the TNI because they feared that the PKI would become a fifth column as a military militia against the TNI if a civil war occurred. The force itself had been trained by the Indonesian Air Force at Lubang Buaya near its headquarters at Halim Perdanakusuma Airport.
By 1965, at the height of the Cold War, the PKI had extensively penetrated all levels of government. With the support of Sukarno and the air force, the party gained increasing influence at the expense of the army, thus ensuring the army's enmity. By late 1965, the army was divided between a left-wing faction allied with the PKI and a right-wing faction that was being courted by the United States.
In need of Indonesian allies in its Cold War against the Soviet Union, the United States cultivated a number of ties with officers of the military through exchanges and arms deals. This fostered a split in the military's ranks, with the United States and others backing a right-wing faction against a left-wing faction leaning towards the PKI.
Insurgency on 1 October
Kidnapping and murder of generals
At around 3:15 am on 1 October, seven detachments of troops in trucks and buses dispatched by Lieutenant Colonel Untung Syamsuri (commander of Tjakrabirawa, the presidential guard), comprising troops from the Tjakrabirawa Regiment (Presidential Guards), the Diponegoro (Central Java), and Brawijaya (East Java) Divisions, left the movement's base at Halim Perdanakusumah Air Force Base, just south of Jakarta to kidnap seven generals, all members of the Army General Staff. Three of the intended victims, (Minister/Commander of the Army Lieutenant General Ahmad Yani, Major General M. T. Haryono, and Brigadier General D. I. Pandjaitan) were killed at their homes, while three more (Major General Soeprapto, Major General S. Parman, and Brigadier General Sutoyo) were taken alive.
Ahmad Yani famously slapped a Cakrabirawa soldier before he was shot. During the encounter, a Cakrabirawa soldier told Ahmad Yani that he was summoned by President Sukarno. Yani was willing to go but he wanted to take a bath first, however another soldier denied him that request. Ahmad Yani was furious and slapped that soldier on the face.
Meanwhile, their main target, Coordinating Minister for Defense and Security and Armed Forces Chief of Staff, General Abdul Haris Nasution managed to escape the kidnap attempt by jumping over a wall into the Iraqi embassy garden. However his personal aide, First Lieutenant Pierre Tendean, was captured after being mistaken for Nasution in the dark. Nasution's five-year-old daughter, Ade Irma Suryani Nasution, was shot by the assault group and died on 6 October. In addition a police officer guarding Nasution's neighbor Johannes Leimena, Police Chief Brigadier Karel Sadsuitubun, was shot and killed by the kidnapping group. A final victim was Albert Naiborhu, General Pandjaitan's nephew, who was killed during the raid on the General's home. The generals and the bodies of their dead colleagues were taken to a place known as Lubang Buaya near Halim where those still alive were shot dead. The bodies of all the victims were then thrown down a disused well near the base.
Takeover in Jakarta
Later that morning, around 1,000 troops from two Java-based divisions (the 454th Infantry Battalion from the Diponegoro Division and the 530th Infantry Battalion from the Brawijaya Division) occupied Lapangan Merdeka, the park around the National Monument in central Jakarta, and three sides of the square, including the Radio Republik Indonesia (RRI) main building and studios. They did not occupy the east side of the square – the location of the armed forces strategic reserve (KOSTRAD) headquarters, commanded at the time by Major General Suharto. At some time during the night, D. N. Aidit, the Communist Party of Indonesia (PKI) leader, and the Commander of the Indonesian Air Force and Minister of the Air Force, Air Marshal Omar Dani, both went to the Halim AFB, which pointed to their involvement in the movement.
Following the news at 7 am, RRI broadcast a message from Lieutenant Colonel Untung Syamsuri, commander of the 1st Honor Guard Battalion (Army), Tjakrabirawa Regiment, to the effect that the 30 September Movement, an internal Indonesian Army organization, had taken control of strategic locations in Jakarta, with the help of other military units. They proclaimed that this was to forestall a coup attempt by a 'Generals' Council' aided by the Central Intelligence Agency, intent on removing Sukarno on the upcoming 20th Armed Forces Day, 5 October. It was also stated that President Sukarno was under the movement's protection. Sukarno traveled to Halim 'after learning that there were troops near the Palace on the north side of Lapangan Merdeka' and also claimed (later) 'that this was so he could be near an aircraft should he need to leave Jakarta'. Further radio announcements from RRI later that day listed 45 members of the G30S Movement and stated that all army ranks above Lieutenant Colonel would be abolished. While at Halim, the president met with Deputy Prime Minister Johannes Leimena and the navy and police commanders, along with the attorney general and the palace guard chief to plan for a replacement to the post of Commander of the Army which was by now vacant.
The end of the movement in Jakarta
At 5.30 am, Suharto, commander of the Army's Strategic Reserve (KOSTRAD), was woken up by his neighbor and told of the disappearances of the generals and the shootings at their homes. He went to Kostrad HQ and tried to contact other senior officers. He managed to contact and to ensure the support of the commanders of the Navy and the National Police, but was unable to contact the Air Force Commander. He then took command of the Army and issued orders confining all troops to their barracks.
Because of poor planning, the coup leaders had failed to provide provisions for the troops on Lapangan Merdeka, who were becoming hot and thirsty. They were under the impression that they were guarding the president in the palace. Over the course of the afternoon, Suharto persuaded both battalions to give up without a fight, first the Brawijaya battalion, who came over to Kostrad HQ, then the Diponegoro troops, which withdrew to Halim. His troops gave Untung's forces inside the radio station an ultimatum and they also withdrew. By 7 pm Suharto was in control of all the installations previously held by the 30 September Movement's forces. Now joined by Nasution, at 9 pm he announced over the radio that he was now in command of the Army and that he would destroy the counter-revolutionary forces and save Sukarno. He then issued another ultimatum, this time to the troops at Halim. Later that evening, Sukarno left Halim and arrived in Bogor, where there was another presidential palace.
Most of the rebel troops fled, and after a minor battle in the early hours of 2 October, the Army regained control of Halim, Aidit flew to Yogyakarta and Dani to Madiun before the soldiers arrived.
Events in Central Java
Following the 7 am radio broadcast on RRI, troops from the Diponegoro Division in Central Java took control of five of the seven battalions and other units in the name of the 30 September movement. The PKI mayor of Solo, Utomo Ramelan, issued a statement in support of the movement. Rebel troops in Yogyakarta, led by Major Muljono, kidnapped and later killed Col. Katamso and his chief of staff Lt. Col. Sugiyono. However, once news of the movement's failure in Jakarta became known, most of its followers in Central Java gave themselves up. On 5 October, both Katamso and Sugiyono, the commander and executive officer of the 72nd Military Area at the time of their murders, were also posthumously named Heroes of the Revolution by Sukarno, also in his capacity of Commander of KOTI.
Aftermath
Funeral
On 4 October, the bodies of all seven casualties were recovered from the well in which they were thrown at Lubang Buaya. They were buried in a state funeral on 5 October, Armed Forces Day, preceded by an address by Nasution.
All seven Army officers and the police brigadier were, by order of President Sukarno in his capacity as the Commander of the Supreme Operations Command (Panglima Komando Operasi Tertinggi/Panglima KOTI), officially declared the very same day as Heroes of the Revolution posthumously per Decree of the President/Commander of KOTI No. 111/KOTI/1965.
President Sukarno himself did not attend the funeral. Minister for Foreign Affairs Subandrio acted as the ceremony inspector for the funeral, and General Nasution was reportedly bowing in front of Pierre Tendean's body as a gesture of respect for his loyalty and sacrifice.
Anti-communist purge
Suharto and his associates immediately blamed the PKI as masterminds of the 30 September Movement. With the support of the Army, and fueled by horrific tales of the alleged torture and mutilation of the generals at Lubang Buaya, anti-PKI demonstrations and then violence soon broke out. Violent mass action started in Aceh, then shifted to Central and East Java. Suharto then sent the RPKAD paratroops under Col. Sarwo Edhie to Central Java. When they arrived in Semarang, locals burned the PKI headquarters to the ground. The army swept through the countryside and were aided by locals in killing suspected communists. In East Java, members of Ansor Youth Movement, the youth wing of the Nahdlatul Ulama went on a killing frenzy, and the slaughter later spread to Bali. Figures given for the number of people killed across Indonesia vary from 78,000 to one million. Among the dead was Aidit, who was captured by the Army on 21 November and summarily executed shortly after. Records from the United States Department of State indicate that the U.S. embassy in Jakarta tracked the killings of these leftists, and that U.S. officials "actively supported" the efforts of the Indonesian Army to quell the labour movement. US Ambassador Marshall Green advised the Suharto government to "Spread the story of PKI‘s guilt, treachery and brutality" and assisted by providing detailed lists of thousands of PKI members to the military and anti-communist civilians.
Several hundred or thousand Indonesian leftists travelling abroad were unable to return to their homeland. Djawoto, the ambassador to China, refused to be recalled and spent the rest of his life outside of Indonesia. Some of these exiles, writers by trade, continued writing. This Indonesian exile literature was full of hatred for the new government and written simply, for general consumption, but necessarily published internationally.
Commemoration
Immediately following Suharto's appointment as President in 1967, 1 October was decreed as Pancasila Sanctity Day (Indonesian: Hari Kesaktian Pancasila). The government's official narrative is that the day is commemorated to celebrate the triumph of Pancasila over all ideologies, especially "Communism/Marxism-Leninism" (sic; official terminology). It is still commemorated to this day.
Under the New Order and to this day, the movement is usually referred to as the Thirtieth of September Movement/PKI (Indonesian: Gerakan 30 September/PKI or "G30S/PKI"). The name of Betrayal of PKI (Pengkhianatan PKI) is also used for the museum in East Jakarta to remember its history. The houses of Yani and Nasution in Central Jakarta have also become museums.