Battle of Ambon

The Battle of Ambon (30 January – 3 February 1942) occurred on the island of Ambon in the Dutch East Indies (Indonesia), during World War II. A Japanese invasion was resisted by Dutch and Australian forces. The chaotic and sometimes bloody fighting was followed by a series of major Japanese war crimes.

Background
During 1941, as the Allies perceived the possibility of war with Japan, Ambon was seen to be a strategic location, because of its potential as a major air base. The Australian government and military commanders saw that it could be used in raids on northern Australia and decided to reinforce the Dutch forces on the island. On 14 December 1941 a convoy composed of escorts Adelaide and Ballarat with the Dutch ships Both, Valentijn, and Patras carrying 1,090 troops of "Gull Force" departed Darwin and arrived at Ambon on 17 December. HMAS Swan escorting Bantam arrived with reinforcements on 12th January 1942, remaining through raids on the 15—16th until the 18th.

Geography
Ambon is located in the Maluku (Moluccas) islands, just south of the much larger island of Seram (Ceram). 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 — northern part of the island — facing the Bay of Ambon. The town of Ambon is at the opposite side of the bay, on the southern part of the island, Laitimor Peninsula.

Allies
At the outbreak of war on 8 December, 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 Lt. Col. Leonard Roach, arrived on 17 December. The force consisted of the Australian 8th Division's 2/21st Infantry Battalion, as well as some divisional artillery and support units. Kapitz was appointed Allied commander on Ambon. Roach had visited the island before Gull Force's deployment and requested that more artillery and machine gun units be sent from Australia.

On 6 January, after Dutch and British territories to the north fell to Japan, Ambon came under attack from Japanese aircraft. Roach complained about the lack of response to his suggestions, and as a result he was replaced by Lt. Col. John Scott on 14 January.

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 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 AA guns, four 40 mm AA guns, a AA machine gun platoon and a AA machine gun battery.

However, Lt Col. Scott, Gull Force HQ 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.

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 Buffalos, two crashed en route to Ambon. The Royal Australian Air Force sent two flights, comprising 12 Lockheed Hudson Mk 2 light bombers, from No. 13 and No. 2 Squadrons, were deployed to the area, under Wing Commander Ernest Scott (who was not related to Lt Col. 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 TEN, with PBY Catalinas, based at the Halong seaplane station from 23 December. Wing Headquarters moved to Java 9 January, but American PBYs mounted patrols from Halong through the 15 January air raid, and then abandoned the base as too exposed. Altogether five USN PBYs were destroyed there by air attack. The Wing’s seaplane tenders supported patrols, but left after 8 January. Tender-based patrols from William B. Preston (AVD 7) and Heron (AVP 2) 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 they were ordered to Java.

U. S. Navy and RAAF aircraft made several very dangerous evacuation flights into Ambon/Laha in the last days of January.

Gouden Leeuw, a Royal Netherlands Navy minelayer, left Ambon in early January, after mining approaches to the island. By mid-January, Heron was the only Allied combat ship at Ambon.

Japan
An Imperial Japanese Navy (IJN) task force for the invasion of Ambon, commanded by Rear Admiral Ibō Takahashi, included the aircraft carriers Hiryū and Sōryū, two seaplane tenders, the heavy cruisers Nachi and Haguro, the light cruiser Jintsu, 15 destroyers, five minesweepers, four submarine chasers and two patrol boats.

The Japanese ground forces were made up of about 5,300 personnel: the Itō Detachment of the Imperial Japanese Army (IJA), under Major General Takeo Itō, comprising the 38th Division HQ and the 228th Infantry Regiment, along with marines from the 1st Kure Special Naval Landing Force (part of the China Area Fleet), under Rear Admiral Koichiro Hatakeyama.

30 January
From 6 January onwards, Ambon was attacked by Japanese aircraft. Allied aircraft made some sorties against the approaching Japanese fleet, with little success. On 13 January, the two Buffalos, piloted by Lt Broers and Sgt Blans, attacked a flight of 10 Zero fighters. Broers' plane was hit and caught fire, but he continued to attack until it became uncontrollable, at which point he abandoned the Buffalo, using his parachute and landed in the sea. Blans was also shot down but also managed to use his parachute, landing in trees on Ambon. Both men were rescued. Broers suffered severe burns and Blans had 17 different wounds.

The naval aviation base at Halong was soon rendered unusable by Japanese air raids, and was abandoned by the Dutch and US navies in mid-January.

On 30 January, about 1,000 Japanese marines and IJA personnel landed at Hitu-lama on the north coast. Other elements of the 228th Regiment landed on the southern coast of the Laitimor Peninsula. Although the Japanese ground forces were numerically not much bigger than the Allies, the Japanese had overwhelming superiority in air support, naval and field artillery, and tanks. The remaining Allied aircraft were withdrawn that day, although RAAF ground staff remained. Within a day of the Japanese landings, the Dutch detachments in their vicinity were overrun and/or had withdrawn towards Paso. The destruction of bridges on Hitu was not carried out as ordered, hastening the Japanese advance.

There was a second wave of landings, at Hutumori in south eastern Laitimor, and at Batugong, near Paso. An Australian infantry platoon was detached to reinforce the pioneers on Nona plateau. The defences at Paso had been designed to repel attacks from the north and west, and now faced assault from the south. A KNIL platoon was detached from Paso to resist the attack on Batugong, causing a gap in the Dutch lines. The Japanese took advantage of this, and were assisted by the failure of a KNIL telephone line.

31 January
Batugong fell in the early hours of 31 January, enabling the Japanese to encircle the eastern flank of the Passo positions. Meanwhile, Kapitz ordered the Ambonese KNIL company at Eri to take up a position at Kudamati, which appeared prone to attack.

At noon on 31 January, Kapitz moved his headquarters from Halong to Lateri, closer to Passo. Telephone communications between Kapitz and his subordinates, including Lt Col. Scott, ceased when the Japanese cut the lines. The Japanese force which had landed at Hitu-Lama then attacked the Passo defences from the north-east. Then, in the words of the Australian official historian:


 * [a]t 6 p.m. a motor-cycle with sidecar was seen on the road to the west of the Passo position showing white flags and travelling towards the Japanese. Firing on the Passo perimeter was suspended on the orders of the Dutch company commanders, and the troops were allowed to rest and eat.

It is not clear who authorised the surrender. There was no immediate response from the Japanese, and — in a meeting with company commanders — Kapitz and Tieland ordered the Dutch troops to recommence fighting. However, when Tieland and the company commanders returned to their positions, they found that their troops had been taken prisoner, and they were forced to surrender.

The first land attack on Laha occurred on the afternoon of 31 January. An Australian platoon north-east of the airfield was attacked by a stronger Japanese force, which it repelled.

Japanese forces were also approaching the town of Ambon from the south west. At about 4 p.m. on 31 January, the Japanese captured the town, including an Australian casualty clearing unit.

1 February
Several Japanese attacks were launched simultaneously on 1 February: The Australian positions were also receiving large numbers of Dutch personnel fleeing from Paso. At 10:30 p.m., Scott ordered a withdrawal of the Allied forces at Amahusu and the south west, to Eri. The position at Kudamati was effectively encircled.
 * Kapitz and his headquarters staff were taken prisoner in the early hours. Kapitz surrendered the remaining forces in the Paso area and sent a note to Lt. Col. Scott urging him to do the same. (The message did not reach Scott for two days.)
 * an Australian transport unit and KNIL positions at Kudamati were attacked by infantry
 * mountain guns in high ground were shelling a Dutch artillery battery on the coast at Benteng, which was forced to withdraw, putting further pressure on Kudamati.
 * infantry attacked the eastern flank of Australian positions at Amahusu.
 * on Nona plateau, a foothold was established in spite of fierce Australian opposition.
 * Japanese aircraft and naval artillery attacks on the positions at Eri.

2–3 February
On 2 February (some sources say 1 February), the Japanese minesweeper W-9 struck a mine laid by the Dutch minelayer Gouden Leeuw in the Bay of Ambon and sank. Two other Japanese minesweepers were also damaged by mines.

After dawn on 2 February, the main Australian force on Nona plateau, commanded by Lieutenant Bill Jinkins, was in danger of encirclement. Jinkins ordered a withdrawal to Amahusu, where he became aware that the Dutch had surrendered. Unable to ascertain the disposition of Lt Col. Scott's force, Jinkins decided to meet senior Japanese officers under truce at the town of Ambon. They allowed him to speak to Kapitz, who wrote another note advising the Australian commander to surrender. Jinkins set off to find Lt Col. Scott.

Meanwhile, the Japanese forces attacking Laha were reinforced and a concentrated assault on the Allies began, including naval artillery, dive bombers, fighter planes and probing attacks by infantry. A Japanese night attack in high grass near the beach, between two Allied positions, was beaten back by an Australian platoon. However, a massive Japanese offensive commenced at dawn on 2 February. By 10 a.m., only about 150 Australians and several KNIL personnel were still able to fight at Laha, and Newbury ordered them to surrender.

By the morning of 3 February, the Australians around Eri were struggling to cope with increasing air and naval attacks, wounded Australians, the influx of Dutch personnel, diminishing supplies and widespread fatigue. A Japanese flag had been seen flying on the other side of the bay, at Laha. By the time Jinkins reached Lt Col. Scott, the latter had himself met the Japanese and decided to surrender. The Allied position at Kudamati was surrendered separately at midday.

Laha massacre
Allied casualties in the battle were relatively light. However, at intervals for a fortnight after the surrender, IJN personnel chose more than 300 Australian and Dutch prisoners of war at random and summarily executed them, at or near Laha airfield. In part this was revenge for the sinking of the Japanese minesweeper, as some surviving crew of the minesweeper took part. Those killed included W/Cdr Scott and Maj. Newbury. According to an Australian War Memorial principal historian, Dr Peter Stanley, over the following three and a half years, the surviving POWs:


 * ...suffered an ordeal and a death rate second only to the horrors of Sandakan, first on Ambon and then after many were sent to the island of Hainan [China] late in 1942. Three-quarters of the Australians captured on Ambon died before the war's end. Of the 582 who remained on Ambon 405 died. They died of overwork, malnutrition, disease and one of the most brutal regimes among camps in which bashings were routine.

In 1946, incidents which followed the fall of Ambon became the subject of one of the largest ever war crimes trials: 93 Japanese personnel were tried by an Australian military tribunal at Ambon. R. Adm Hatakeyama was found to have ordered the Laha massacres, however he died before he could be tried. Commander Kunito Hatakeyama, who was in direct command of the massacres, was sentenced to execution by hanging. Lieutenant Kenichi Nakagawa was sentenced to 20 years imprisonment. Three other Japanese officers were executed for mistreatment of POWs and/or civilians on other occasions, during 1942–45. (The trials were the basis for the feature film Blood Oath, released in 1990.)

General Itō was sentenced to death that same year for war crimes committed in other parts of the Pacific.

Other subsequent events
Approximately 30 Australian soldiers, including Jinkins, escaped from Ambon, in the space of several weeks after the surrender, often by rowing prahus (canoes) to Seram.

Another result of the capture of Ambon was the realisation of Australian fears of air attacks, when Japanese planes based at Ambon took part in major air raids on Darwin, Australia on 19 February.