The people of North Sumatra were fully aware of their country independence only after Teuku Mohammad Hassan, the local governor, announced the proclamation on 27 August 1945. Just a week before, they were still confused when the Allies’ warplanes showered pamphlets upon their head informing the Japanese’ surrender and the coming Allies’ entry as the savior.
To anticipate the Dutch comeback, many people mostly the youths enthusiastically joined the combatant unit headed by Achmad Tahir, who later became one of the President Soeharto’s ministers, which was proven to be beneficial in facing the situation in the months ahead.
Following the Civil Affairs Agreement between the British and the Dutch, the British was given the full power to handle the situation in the country. However, in September 1945, preceding the British arrival, the Dutch dispatched and posted band of KNIL in Medan, whose one of the commanders was an obscured captain named Westerling. He started to set up an intelligence network and do atrocity things to deter local people.
But nobody was receded from the determination to defend the independence. On 6 October, the day when the public meeting was held at Merdeka Square, the city changed into sea of red-and-white, colored by the flags hoisted at the buildings taken over from Japanese and waved by people marching down the streets in big parades bringing banners written “down with imperialism”.
As anticipated, on 9 October NICA followed-suit hitchhiking from behind the British troops with their Gurkha units who landed in Medan. Brigadier General T.E.D. Kelly, the British commander, soon told local government that his troops just wanted to carry out humanity orders evacuating the Japanese detainees in Medan and in the surrounding areas.
Getting support from British army, NICA officials started to launch provocations which deteriorated the situation. One of the incidents was triggered by an overacting NICA who took off a red-and-white badge worn by a passing boy in front of Medan Hotel and trampled over it. People who happened to see the event were very angry and soon armed clashes spread throughout the area. In Brastagi, angry local people killed a band of British soldiers who lowered a red and white flag from a government building.
To prevent the situation being aggravated, the Allies banned locals from bringing firearms. They handed over the security outside Medan city to Japanese troops under the commander of Lieutenant General Tanabe, the Japanese commander in Sumatra, while they retained the security inside the city under their responsibility. The signposts of “Fixed Boundaries Medan Area” were put at every corner of the city to mark the separation of the two zones.
By then NICA agents and British soldiers could concentrate their power in the city. They were supported by Poh An Thui, a group of Chinese merchants who didn’t believe on the future of the Republic. The later openly took side with British and NICA, hoping that they would get back their trading monopoly. The British allowed Poh An Thui members to own firearms and act as security guards on their behalf.
Frequently in the middle of the battle, the Republicans who were fighting against the Allies got the shots from behind whose actors were nobody but the members of Poh An Thui. They never confronted directly face to face with the combatants and soon after stabbing from behind they run away disappeared into their hidden places.
Poh An Thui operated not only in Medan city but broadened outside mainly in the areas along the Medan-Binjai front line. The local young people used to sing Mariam Tomong, a modified song dedicated to Poh An Thui Chinese members who were cynically considered as cowardice.
One of the big incidents outside the Fixed Boundaries Medan Area took place in Tebingtinggi on 11 December. The Japanese troops who camped in Bahilang Plantation nearby had been on board the train in the direction of Medan with their full arms on hands ready to be repatriated when the local combatants asked them to surrender their arms and go without. At the end they finally agreed to submit part of their machine guns, rifles, pistols and several thousand bullets.
In the afternoon, having learned that 40 of his troops had been killed by the combatants, Major General Sawamaru, the commander in Bahilang, ordered his troops to encircle and attack Tebingtinggi. Achmad Tahir, TKR Commander of North Sumatra 4th Division, threatened Sawamaru that his troops would attack the Japanese at every spots in North Sumatra if they didn’t stop their brutal deeds.
The Japanese finally receded from Tebingtinggi and went back to their camp. During four days of incidents around 3,000 people and 250 Japanese troops were killed. Later on, it was found that those 40 Japanese troops were killed by NEFIS, the Dutch agents, which successfully triggered the clash between the Republicans and the Japanese.
The Medan Area battles took place almost daily along the front lines encircling the city. In the western line extended from Labuan to Tanjung Morawa, the combatants were headed by Major Hasan Achmad struggling to prevent the Allies moving toward Aceh. The troops in the northern front line which was extended from Hamparan Perak to Labuan Belawan, mostly originated from Aceh headed by Lieutenant Amir Yahya. This front line was separated from the southern line which extended from Kampung Alang to Asam Kumbang, by a road in parallel with Medan-Binjai railway. The troops who defended the south line were headed by Major Martinus Lubis.
However, by April 1946, the Allies were able to occupy Medan city but the TKR who retreated to Pematang Siantar made constant counterattacks months after months. On 10 August the TKR commanders held a meeting in Tebingtinggi to unify Medan Area People Regiments under one command.
The Dutch army attacks culminated on 21 July 1947, the beginning of the First Police Action, where they landed at Cermin beach supported by 2 Mustangs and 7 battleships. The battles never receded and continued until the recognition of the Indonesian sovereignty by the Dutch on 27 December 1949.