The Battle of Ambon (30 January – 3 February 1942) occurred on Ambon Island in the Dutch East Indies (now Indonesia), as part of the Japanese offensive on the Dutch colony during World War II. In the face of a combined defense by Dutch and Australian troops, Japanese forces conquered the island and its strategic airfield in several days. In the aftermath of the fighting, a major massacre of many Dutch and Australian prisoners of war by the Imperial Japanese Army (IJA) followed. Following the war, many of the IJA personnel were tried for war crimes.
Background Ambon is located in the Maluku (Moluccas) islands, just south of the much larger Seram Island. Ambon has what might be described as a "figure eight" or "hourglass" shape, and consists of two peninsulas separated by a narrow isthmus, with long narrow bays on either side of the isthmus. The key airport at Laha is in the west of the Hitu Peninsula, at the northern part of the island facing Ambon Bay. The town of Ambon is at the opposite side of the bay, on the southern part of the island on Laitimor Peninsula.
Despite being one of the islands of the Dutch East Indies' outlying regions, the Dutch knew Ambon had strategic importance as an airbase and had been reinforcing its defense since 1941, adding Royal Netherlands East Indies Army troops from Java. Yet as far back as 1940, Australia also saw the island's significance as a nearby stepping-stone for Japanese forces to attack Australia from the north. In an agreement with the Dutch government-in-exile (which still held a neutral stance on Japan in 1940), Australia agreed to bolster Dutch defenses by sending in troops and equipment to Ambon and Timor islands. Brigadier Edmund Lind, commander of the Australian 23rd Brigade, held significant reservations about sending troops to Ambon, given the lack of firepower and air assets available to the Australian troops, in addition to an absence of Australian military liaison units embedded with the local Dutch forces.
On 14 December 1941 a convoy composed of escorts and with the Dutch ships Both, Valentijn, and Patras carrying 1,090 troops of "Gull Force" departed Darwin and arrived at Ambon on 17 December. escorting Bantam arrived with reinforcements on 12 January 1942, remaining through raids on 15–16 January until 18 January.
Order of Battle
Japan
Ground Forces Eastern Detachment (Commander: Maj. Gen. Takeo Itō)Units under direct commandLeft Assault Unit (Commander: Col. Sadashichi Doi)Right Assault Unit (Commander: Col. Eijirō Kimura)1st Kure Special Naval Landing Force (Commander: Kunito Hatakeyama) Eastern Detachment HQ One squad of the 38th Divisional Signal Unit 3rd Company of 23rd Antiaircraft Artillery Regiment 1st Company of 44th Field Antiaircraft Artillery Battalion One independent engineer company 38th Divisional 1st Field Hospital (minus one half) One platoon of the 38th Transport Regiment 228th Infantry Regiment HQ One platoon of 3rd Company 4th Company 228th Infantry Regiment Signal Unit (minus three squads) 38th Divisional Signal Unit (minus two squads) Main strength of the 38th Divisional Medical Unit2nd Battalion One squad of the 228th Infantry Regiment Signal Unit 4th Company of the 38th Mountain Artillery Regiment 3rd Company of the 38th Engineer Regiment (minus one platoon) One squad of the 38th Divisional Signal Unit 2nd Battery of the 2nd Independent Antitank Gun Battalion Element of the 38th Divisional Medical Unit10th Company of the 228th Infantry Regiment
Naval Forces Eastern Attack Unit (Commander: Rear. Adm. Takeo Takagi):2nd Destroyer Flotilla (Commander: Rear. Adm. Takeo Takagi):Air Group 2nd Air Unit
(Commander: Cdr. Ruitarō Fujita)Base Force (1st Base Unit) (Commander: Rear. Adm.
Kyūji Kubo): - 2nd Escort Unit (Commander: Rear. Adm. Raizō Tanaka): 2nd Destroyer Squadron (Jintsu) 8th Destroyer Division (Ōshio, Asashio, Michishio) 15th Destroyer Division (Natsushio, Kuroshio, Oyashio, Hayashio) 16th Destroyer Division (Yukikaze, Tokitsukaze, Hatsukaze, Amatsukaze) - Transport Unit
1st Echelon: Yamaura Maru, Africa Maru, Zen’yō Maru, Miike Maru 2nd Echelon: Kirishima Maru, Yamafuku Maru, Yamagiri Maru, Lyons Maru, Hino-maru No. 5, Katsuragi Maru11th Seaplane Division (Chitose, Mizuho) Patrol Boat P-39Patrol boat P-34 21st Minesweeper Division (W-7, W-8, W-9, W-11, W-12) 1st Submarine-chaser Division (Ch 1, Ch 2, Ch 3)
Netherlands Molukken Brigade (Commander: Lt. Col. Joseph R.L. Kapitz):InfantryArtilleryOther UnitsMoluccas Garrison Battalion (Commander: Major H.H.L. Tieland) 1st Company (Javanese KV Company) under Capt. H.A. de Jongh Swemer 2nd Company (various ethnicities), under Capt. E.P. Bouman 3rd Company (Ambonese), under Capt. A.G.M. Schouten 4th Company (various ethnicities), under Capt. J. Kaseger 5th Company (European Militia), under 1st. Lt. W.A. Blauboer Machine Gun Company under 1st Lt. F.E.A.H. de Jong; Five sections of two Vickers machine guns, three sections of four 80 mm mortars, two 20mm anti-tank guns, and four 7.7mm AA machine guns. Four overvalwagen armored cars. Boela Detachment under 1st Lt. Raden Didi Kartasasmita: 4 brigades of ca. 15 men from the Wahai town on Seram Island, as well as Geser Island Reserve Corps Oud Militairen - RK (Commander: Capt. L.G.H. Uckerman): Two understrength companies Depot Battalion Native Militia (Commander: Captain H.M.J. Hesterman): ca. 300 untrained troops Home and Country Guard (Commander: 1st Lt. J. Creutz Lechleitner): Home guard stationed in the cities, Country guard in the countryside4th Company Coast and Anti-Aircraft Artillery (450 men under Reserve Capt. D. Buur) Coastal artillery: One battery of 4x 150 mm L.40 gun (Nona Battery) under reserve 1st Lt. T.L.D. Count. 2 x 75 mm L.55 gun 2 x 37 mm gun Field artillery: Two batteries of 4x 75 mm L.30 guns each under 1st. Lt. P. Jager Gerlings. 4 x 70 mm L.14 gun Anti Aircraft artillery: Two sections of 2x 40 mm AA guns (one at Halong naval base and one at Laha airfield) Three sections of 3x 12.7 mm AA machine guns (one at Halong, one at Laha and one at Nona Battery) Engineer detachment under Capt. W.J.F. van Dun: Liaison and searchlight personnel Maritime Resources Command (CMM) under Capt. Lt. Cmdr. J.J. Jager
Australia
Gull Force (Commander: Col. Leonard Roach, replaced on 14 January by William Scott):Gull Force HQ 2/21 Battalion C Troop of the 18th Australian Anti-Tank Battery One Section of the 2/11th Australian Field Company One Detachment of the 23rd Australian Infantry Brigade Signals Section One Section of the Australian Army Service Corp (AASC) One Detachment of the 2/12th Australian Field Ambulance 23rd Australian Dental Unit 104th Australian Light Aid Detachment One Detachment of the Canteens Services One Detachment of the Intelligence Corps
United States
Patrol Wing 10 (Commander: Capt. Frank D. Wagner): Eight Consolidated PBY Catalina
Prelude Allies Infantry At the outbreak of war on 8 December 1941 Ambon was garrisoned by the 2,800-strong Molukken Brigade of the Royal Netherlands East Indies Army (KNIL) garrison, commanded by Lieutenant Colonel Joseph Kapitz and consisting of Indonesian colonial troops under European officers. The garrison was poorly equipped and trained, partly as a result of the Netherlands having been defeated and occupied by Nazi Germany. The KNIL units were not equipped with radios and relied on landlines and written communications. They included 300 partly trained reservists. The Australian Army's 1,100-strong Gull Force, commanded by Lieutenant Colonel Leonard Roach, arrived on 17 December. The force consisted of the 2/21st Battalion from the Australian 8th Division, as well as some divisional artillery and support units. Kapitz was appointed Allied commander on Ambon. On the very day the Gull Force disembarked in Ambon, Roach raised concerns that mirrored those expressed by Lind. Roach raised concerns about the lack of reconnaissance missions being conducted, medical equipment, anti-tank weapons and the absence of any field guns. This request was repeated on 23 December 1941, to which Army Headquarters rejected and reiterated the need to defend with the supplies available.
On 6 January 1942, after Dutch and British territories to the north fell to Japan and a bombing run on Ambon by Japanese aircraft, Roach once again raised concerns with Army Headquarters and stated that his forces could hold out for no more than one day without reinforcements. Following this communication, Roach was relieved of command and was replaced by Lieutenant Colonel John Scott on 14 January. This change in command caused significant problems as Scott had no prior knowledge of the situation in Ambon and was not acquainted with much of the Gull Force. Throughout early to late January, many troops of Gull Force were taken out of action because of malaria and dysentery.
Kapitz's headquarters was at Halong, between Paso and the town of Ambon. It included four armoured cars, an anti-aircraft machine gun detachment and four 40 mm anti-aircraft (AA) guns. In the belief that the terrain on the south coast of Laitimor was too inhospitable for landings and that any attack was likely to be in the east, around the Bay of Baguala, the KNIL forces were concentrated at Paso near the isthmus, under Major H. H. L. Tieland. There were small KNIL detachments at likely landing places in the north of Hitu.
Two companies of the 2/21st Battalion and 300 Dutch troops were at Laha Airfield, under the command of Major Mark Newbury. They were accompanied by Dutch artillery: four 75 mm field artillery pieces, four 37 mm anti-tank guns, four 75 mm anti-aircraft (AA) guns, four 40 mm AA guns, an AA machine gun platoon and an AA machine gun battery.
However, Scott and the remainder of the Australian troops were concentrated in the western part of Laitimor Peninsula, in case of an attack from the Bay of Ambon. "A" Company of the 2/21st and one KNIL company were stationed at Eri, on the south west side of the bay. The 2/21st Battalion's pioneer platoon was on the plateau around Mt. Nona (the highest point on Laitimor), with a Dutch anti-aircraft machine gun detachment. Smaller Australian detachments were at: Latuhalat, near the south western tip of Laitimor and at Cape Batuanjut, just north of Eri. Gull Force HQ and a strategic reserve, "D" Company, were located on a line from the Nona plateau to Amahusu beach, between Eri and the town of Ambon.
Air Forces The Allies had few aircraft to spare. The KNIL Air Service sent No. 2 Flight, Group IV (2-Vl. G.IV) from Java to Laha. Of an original four Brewster F2A Buffalos, two crashed en route to Ambon. The Royal Australian Air Force (RAAF) sent two flights, comprising 12 Lockheed Hudson Mk 2 light bombers, from No. 13 and No. 2 Squadrons, to the area, under Wing Commander Ernest Scott (who was not related to Lieutenant Colonel John Scott). One flight was based at Laha, and another was sent to Namlea on the neighbouring island of Buru.
The U.S. Navy's Patrol Wing 10, with Consolidated PBY Catalinas, was based at the Halong seaplane station from 23 December. Wing Headquarters moved to Java on 9 January, but American Catalinas mounted patrols from Halong until 15 January when an air raid destroyed three patrol aircraft and damaged several others. The Allies then abandoned the base as it was too exposed. The Wing's seaplane tenders supported patrols but left after 8 January. Tender-based patrols from and at anchorages further south continued until 5 February.
The Royal Netherlands Naval Air Service (Marineluchtvaartdienst) flew patrols from Ambon/Halong; GVT 17 with Catalina flying boats continued from the start of war through 14 January, when it was ordered to Java.
U.S. Navy and RAAF aircraft made several very dangerous evacuation flights into Ambon/Laha in the last days of January after Allied forces lost all air superiority to Japanese forces.