Battle of Banjarmasin

Prior to 1941, Banjarmasin was the administrative centre for East and South-East Borneo, and seat of the governor of Dutch Borneo. Oelin (Ulin) Airfield that was located 25 kilometers outside the town ranged only 420 kilometers from Surabaya, making it a key target in the Japanese plan to destroy Allied air power in Java prior to their offensive. The Dutch established another airfield at Kotawaringin, 350 kilometers to the west. == Order of Battle ==

Japan Ground Forces • Land Drive Unit (Commander: Col. Kyōhei Yamamoto): • 146th Infantry Regiment (minus 1st and 2nd Battalion) • One artillery battery • One engineer company (minus one platoon) • Medical unit • One transport company • Sea Drive Unit (Commander: Capt. Yoshibumi Okamoto): • One infantry company • One engineer platoon • One independent engineer platoon • One radio squad Netherlands Ground Forces • Kotawaringin (Commander: Lt. G.T.C. Schoenmaker): • Ten brigades (One brigade: ca. 15-18 troops) • Two Lewis guns for AA defense • Dajoe (Dayu) (Commander: Reserve 1st. Lt. W.M.J. van der Poel): • One brigade • 25 militarized field police • Tanahgrogot (Commander: 1st. Lt. W. Michielsen): • 60 troops • Amoentai (Amuntai) and Barabai: • Three Landwacht brigades each, armed with hunting rifled • Kandangan (Commander: Reserve 1st. Lt. D.E.P. Scholte): • Three Landwacht brigades • 25 conscripts • Oelin (Commander: Capt. F. Bolderhey): • Nine brigades (ca. 150 regular infantry and conscripts) • Two 7.7 mm machine gun • Few Lewis guns • Banjarmasin (Commander: Capt. J.H. van Epen) • One Stadswacht company • Six conscript brigades • Two overvalwagens == Dutch Plans ==

Dutch troops in Banjarmasin were mainly tasked with defending both Oelin and Kotawaringin airfields. Despite the essence of the mission the troops came from various groups that were poorly equipped; some units were not provided with uniforms until January 1942. Many of the Stadswacht and Landwacht brigades were only set up in 1941 and had training in handling weapons or maneuvering in battle. Upon completion of the main mission, all soldiers outside Java had to conduct guerrilla warfare. The command staff and governor would relocate to Moearatewe, in North Barito, while the administrative staff would remain behind, hoping to continue working normally after the occupation. Three storage facilities were set up along the route to Moearatewe as part of this. == Japanese Plans ==

Considering that the Japanese did not have any updated intelligence on the condition of the airfields in Banjarmasin, in addition to the lengthy time it would take to set up the airfield for operation once captured, the Navy cancelled its involvement in the operation. Instead, the Army planned to conduct a two-pronged attack on the city from the sea and overland, with the latter being the main thrust. Col. Yamamoto's Land Drive Unit that planned to attack overland will leave Balikpapan on the night of 30 January and land in Tanahgrogot at dawn on the 31st. The Unit would then traverse the jungle and mountains southward, with an element of its force advancing as vanguard to block any Dutch ambush attempts. After moving out of the jungle, it would quickly advance to the city to get ahead of any Dutch efforts to blow up the bridges while retreating. Since provisions were to be procured mostly on site, troops only carried nine days worth of rations with them. Meanwhile, Capt. Okamoto's Sea Drive Unit, would leave a few days before Yamamoto's Unit. Using landing craft, the unit would only move at nighttime. During the day they planned to go upriver near the river mouths and hide under the forest to avoid Allied air reconnaissance. To secure passage through the channel west of Laoet (Laut) Island, Okamoto planned to conduct a night raid on Kotabaroe (Kotabaru) to gather supplies and intelligence. Upon landing at Banjarmasin, the Unit would advance and capture Oelin airfield. Opposite of the Land Drive Unit, Okamoto's troops needed to procure provisions along the advance. == The Battle ==

Prelude Raids After the fall of Tarakan, daily Japanese air raids began to be seen over Banjarmasin. The first Japanese fighters conducted strafing runs on Oelin airfield on 20 January, but caused little damage. During the air raid on 21 January, 4 Mitsubishi Zeros and a Babs reconnaissance plane of the Tainan Air Wing destroyed a PBY Catalina from MLD's 16th Flight Group (GVT.16) that had landed on the Barito Delta. A major loss occurred on 27 January, when eight Glenn Martin bombers stopped by at Oelin en route to the Samarinda II Airfield. When the air raid came, the Lewis Guns that were stationed as AA defense were ineffective against the Japanese planes. The Japanese destroyed six of the bombers and damaged the other two, dealing a severe blow to the Dutch morale. Land Drive Unit The advance party of Yamamoto's Unit left Balikpapan on the morning of 31 January and landed at Adang Bay at 20:00 on the same day. This order brought Halkema in clash with the Dutch Borneo governor, Bauke Jan Haga. Gov. Haga perceived the destruction to be premature, as it would disrupt the economic life in the cities along the Hoeloe Soengei (Hulu Sungei/Sungai), which refers to the line of towns and villages located east of the Barito River. In protest, Gov. Haga sent official complaint to the Dutch army commander, Heinrich ter Poorten, asking for Halkema to be replaced. In agreement, ter Poorten sent Major A. Doup to replace him. At Dajoe, Lt. van der Poel's troops destroyed the small airfield in the town before retreating up north to Boentok (Buntok) and lost communication with the command staff. When the local population mistakenly reported that the Japanese forces are advancing on the town, many of van der Poel's indigenous soldiers and field police deserted, leaving him with five men. On 7 February, Halkema reinforced the troops at Kandangan with two brigades from Oelin (armed with a Madsen machine gun) under the command of 1st. Lt. W.K. Remmert. Remmert had to delay Yamamoto's advance along the Kandangan-Martapoera Road, before regrouping with a conscript brigade at Oelin Airfield. By 11:30, Remmert's troops arrived in Kandangan and began to take up position north of the town, before assisting Scholte in the demolition effort. Both groups then withdrew into a defensive position in Martapoera to protect Oelin Airfield. before moving further up north to Poeroektjaoe (Puruk Cahu). As Halkema drove to Oelin, part of his staff had begun to embark on the ships Irene and Otto. Both ships were directed to steam towards Schans van Tuyl (junction of the Martapoera (Martapura) and Barito River), where they will await further instructions. In the meantime, Banjarmasin's harbormaster ordered a steamboat to head to Takisoeng (Takisung), a coastal town south of Banjarmasin, where it would be at Halkema's disposal. The Borsumij ship steamed on at 19:00; Dutch forces on board that managed to evacuate to Kotawaringin at the time only numbered at 75 troops. After docking at Kotawaringin on the 11th, Halkema and other non-essential personnels left by plane for Java on 12 February, while the infantrymen under Capt. W.C.A. van Beek reinforced the forces at the airfield. On 11 February, he and his troops left in a small 17-meter boat, alongside 180 other Dutch civilians (including 20 women). After sailing in the rough seas for six days, Bolderhey landed in Madura. By nightfall, the Unit had occupied Banjarmasin. Sea Drive Unit Okamoto's Sea Drive Unit left Balikpapan on the evening 30 January on four large and two small landing crafts and began to make their way along the coast southward. In accordance with the plan, the Unit concentrated their advance at rivermouths at night according to plan, with a naval officer attached to pilot the movement. At day, the landing crafts were camouflaged under mangrove forests to avoid detection. Coming through Apar Besar Bay, Pamukan Bay and Klumpang Bay, Okamoto made a night raid on Kotabaroe, encountering no opposition and capturing many supplies and provisions. On 8 February, the Sea Drive Unit landed 80 km from Banjarmasin and advanced without opposition to the Oelin Airfield. Since the Land Drive Unit had already dispersed Halkema's troops, Okamoto's troops reached Oelin Airfield without opposition on 10 February. == Aftermath ==

By the end of the battle, the Land Drive Unit had advanced 400 km south from their landing point in Adang Bay to Banjarmasin, 100 km of which were done through the jungle. Base material for the 11th Air Fleet arrived at Oelin via fishing boats on 20 February, and by the 25th, an element of the 23rd Air Flotilla landed on the airfield, which was soon to be used as a base for the advance to Bali. Kotawaringin Airfield The units that stayed behind at Kotawaringin Airfield were reinforced with the 2/15 Punjab battalion under Lt. Col. M.C. Lane that had arrived exhausted from Miri & Kuching. On 24 February, a ship carrying supplies arrived to provide additional food stocks to the defenders. It was not until late March-early April that the Japanese finally arrived in Kotawaringin and defeated the defenders. Liberation , Commanding Officer, 2/31 Infantry Battalion during the Japanese surrender ceremony. Banjarmasin remained under Japanese occupation until September 1945, when it was liberated by the 2/31st Battalion of the Australian 7th Division. == Notes ==