Battle of Ratsua
Encyclopedia
The Battle of Ratsua occurred during the Second World War
and involved Australia
n and Japan
ese forces. Part of the wider Bougainville Campaign of the Pacific theatre
, the battle took place in the northern sector of Bougainville
between June and August 1945. Following the failed landing at Porton Plantation
in early June, the fighting around Ratsua essentially became a containment action for the Australians as they concentrated their efforts upon driving south towards Buin
, which was the main centre of Japanese resistance on the island at the time. As a result, the situation around Ratsua remained largely static until the end of hostilities in mid August.
in early February 1945, Major General Kesao Kijima
—commander of the Japanese 38th Independent Mixed Brigade— had ordered a withdrawal to Numa Numa, leaving a force of 1,400 sailors drawn from the 87th Naval Garrison Force and 2,000 civilians to hold the Bonis Peninsula. Of these civilians, about 600 were armed, although only half were trained to undertake a combat role. As their supplies dwindled, in May–June the Japanese sailors—under the command of Captain Kato, the senior naval officer in Buka—began to raid the Australian supply lines between Ruri Bay and Ratsua as they attempted to hold a position between Porton Plantation and Tarbut. Meanwhile, Australian troops from the 11th Brigade
had continued their advance north from Tsimba Ridge in April–May, clearing up to the Soraken Peninsula
which was captured by the middle of the month. By the end of May, however, the Japanese fell back behind a series of fortified positions along the base of the Bonis Peninsula, and the Australian advance came to a halt.
In an effort to break this resistance and allow the northwards advance to continue, the Australians attempted to outflank the Japanese line of resistance by launching an amphibious landing at Porton Plantation
on 8 June. The plan called for a reinforced company
from the 31st/51st Battalion
to land behind the Japanese positions and attack from the west, while the main force consisting of the remainder of the 31st/51st Battalion and the 26th Battalion attempted to break through from the south. Due to poor planning, inadequate resources and strong Japanese defence, however, the landing failed at considerable cost to Australians, and as their efforts turned towards effecting a withdrawal from the beachhead and rescuing the stranded men, the attempt by the main force to break through from Ratsua also failed as tired troops came up against strong Japanese defensive positions.
, decided to focus the main effort of the Australian campaign upon driving south towards the Japanese garrison at Buin, where the bulk of the Japanese forces were holding out. In order to concentrate enough forces for the next phase of the operation, however, Savige decided that the 11th Brigade, which had been carrying the advance north, should be relieved so that it could be transferred to the south following a period of rest and reorganisation.
Nevertheless, there was still a need to maintain the pressure upon the Japanese in the north, and so the 23rd Brigade
—which had been previously operating in the central sector after being transferred from garrison duty in the Outer Islands—was also given responsibility for the northern sector as well, relieving the 11th Brigade on 20 June. The brigade's commander—Brigadier Arnold Potts
—was charged with keeping the Japanese force bottled up on the Bonis Peninsula and to send out patrols towards the Buka Passage
. Initially, Potts was only allowed to allocate one of his three battalion
s—the 27th
—for the task, as the other two—the 7th and 8th Battalions—were to remain in the central sector; however, after intelligence reports indicated that the Japanese forces in the northern sector were stronger than the Australians initially thought, he requested permission to transfer the 8th Battalion, along with a battery
of artillery from the 4th Field Regiment that was to be based on the Soraken Peninsula. Due to the requirements of the advance to the south, however, no engineer or armoured support was initially available.
This request was approved, and by 28 June the two battalions and their supporting artillery were assembled; the 8th on the left, or western side of the peninsula, and the 27th on the right, with the artillery based on the Soraken Peninsula. The two battalions sent fighting patrols forward, however, due to the dense terrain, the Australian line of communication
was quite long and the infantry spread out over a very wide area—with each battalion occupying a 4000 yards (3,657.6 m) front, which was twice the normal standard—security of their rear areas became an issue as the Japanese took the opportunity to disrupt the Australian logistic efforts, conducting ambushes, cutting communications and planting mines
along the tracks. As the ambushes increased and casualties mounted, forward movement came to a halt, and by 21 July, the 27th Battalion reported having lost 10 men killed and 36 wounded without having gained any ground.
In light of this failure, the Australian brigade commander requested further resources to undertake a full scale offensive aimed at clearing the Japanese from the peninsula. This request was passed up to corps-level, however, there it was denied as Savige could not afford to release assets that were being used in the drive south. Under pressure to keep casualties to a minimum due to criticism in the media in Australia, Potts formulated a plan to withdraw the 27th Battalion from the right flank and to instead concentrate his forces on the left flank along a 3000 yd (2,743.2 m) front around the plantation at Buoi, to the north of Ratsua. Savige agreed to this on 22 July and the following day the 8th Battalion launched an attack against a feature known to them as "Commo Ridge", where it was believed that the Japanese were attempting to set up a forward position. The attack went in after a preliminary attack from the air, with one company
attacking with two Matilda tanks from the 2/4th Armoured Regiment
in support. Although the airstrike had been largely ineffective and both of the tanks struggled to cross the "swampy ground", the direct fire support provided by the tanks proved decisive and the Australians took the position with in 20 minutes, killing 12 Japanese.
On 24 July, the 8th Battalion launched another attack with two platoon
s assaulting the Japanese position known as "Base 5". Prior to the assault, over 900 artillery shells and mortar bombs were brought down on the Japanese positions in an effort to prepare the position for the attack, however, this proved ineffective against well entrenched positions. The Australians reached their first objective, which was a small ridge in front of the main Japanese position, however, shortly after they began receiving effective fire from concealed positions which killed two men and wounded another in the forward section
, pinning it in place.
Attempts to outflank the bunkers were answered with heavy fire from a medium machine gun and another man was killed and three more wounded. As the attack began to falter, one of the wounded, a 20-year-old private
, Frank Partridge
, who had been injured in the arm and thigh, braved the heavy fire that was being put down towards him and gathered the Bren light machine gun from the man who had been killed. After pouring suppressing fire onto the bunker he discarded the Bren and regathered his rifle, he then rushed towards the bunker with a grenade
, killing its occupants. Partridge's actions reinvigorated the attack and allowed the Australians to take the second Japanese position. After the wounded were recovered, however, they withdrew having lost three men killed and five wounded. Against this eight Japanese were confirmed to have been killed. For his actions during the attack on 24 July, Partridge was awarded the Victoria Cross
, the British Commonwealth's highest military decoration. He was the last Australian to be awarded the medal during the Second World War, and was also the youngest.
Elsewhere, the Australians continued to mount patrols. On 2 August, a patrol from the 27th Battalion was sent out along the Ruri Bay Road in company with two tanks that were to act as their direct fire support. The Japanese were still active in the area, however, and had mined the road with a 500 lb (226.8 kg) bomb which they had rigged to be detonated remotely. The Australian patrol triggered the device and the resulting explosion killed three men in one of the tanks and wounded eight infantrymen following behind. On 5 August, the Australians reoccupied the position at Base 5 after encountering only slight resistance and subsequently named it "Part Ridge". After exploiting the position, it was discovered that the Japanese had built over 60 bunkers in the area, and subsequently they were withdrawn from the ridge again.
On 11 August, in anticipation of the capitulation of Japan following the dropping of two atomic bombs on Japanese cities
, the order to cease offensive combat operations on Bougainville was passed to all Australian units. Three days later, on 15 August, the Japanese Emperor Hirohito
publicly announced Japan's unconditional surrender
, effectively bringing about an end to the war. On 18 August, in the southern sector of the island the Japanese commander, General Masatane Kanda
, dispatched an envoy across the swollen Mivo River to begin negotiations with the Australians for the surrender of the over 23,000 Japanese soldiers left on the island, bringing about an end to the campaign. Throughout the course of the fighting on Bougainville from November 1944 to August 1945, 526 Australians were killed, while a further 1,572 were wounded. It is believed that 8,500 Japanese were killed in action, while a further 9,800 had died from disease during this same period.
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
and involved Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n and Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese forces. Part of the wider Bougainville Campaign of the Pacific theatre
Pacific War
The Pacific War, also sometimes called the Asia-Pacific War refers broadly to the parts of World War II that took place in the Pacific Ocean, its islands, and in East Asia, then called the Far East...
, the battle took place in the northern sector of Bougainville
Bougainville Island
Bougainville Island is the main island of the Autonomous Region of Bougainville of Papua New Guinea. This region is also known as Bougainville Province or the North Solomons. The population of the province is 175,160 , which includes the adjacent island of Buka and assorted outlying islands...
between June and August 1945. Following the failed landing at Porton Plantation
Battle of Porton Plantation
The Battle of Porton Plantation took place at Porton Plantation, near the village of Soraken on Bougainville Island, in the Solomon Islands archipelago during World War II...
in early June, the fighting around Ratsua essentially became a containment action for the Australians as they concentrated their efforts upon driving south towards Buin
Buin, Papua New Guinea
Buin is a settlement at the southern end of the island of Bougainville, a part of the North Solomons Province, located in the northern Solomon Islands in the South Pacific Ocean.-History:...
, which was the main centre of Japanese resistance on the island at the time. As a result, the situation around Ratsua remained largely static until the end of hostilities in mid August.
Background
After their defeat at Tsimba RidgeBattle of Tsimba Ridge
The Battle of Tsimba Ridge was a battle of the Second World War involving Australian and Japanese forces. Part of the wider Bougainville Campaign of the Pacific theatre, the battle occurred in the northern sector of Bougainville Island between 17 January and 9 February 1945, when the lead battalion...
in early February 1945, Major General Kesao Kijima
Kesao Kijima
was a senior officer in the Imperial Japanese Army during World War II.He was the Commanding Officer of the 124th Regiment between 1938 and 1940, before being attached to the 6th Depot Division. Shortly afterwards, he was posted back as the Commanding Officer of the 124th Regiment and served until...
—commander of the Japanese 38th Independent Mixed Brigade— had ordered a withdrawal to Numa Numa, leaving a force of 1,400 sailors drawn from the 87th Naval Garrison Force and 2,000 civilians to hold the Bonis Peninsula. Of these civilians, about 600 were armed, although only half were trained to undertake a combat role. As their supplies dwindled, in May–June the Japanese sailors—under the command of Captain Kato, the senior naval officer in Buka—began to raid the Australian supply lines between Ruri Bay and Ratsua as they attempted to hold a position between Porton Plantation and Tarbut. Meanwhile, Australian troops from the 11th Brigade
11th Brigade (Australia)
The Australian 11th Brigade is an Australian Army brigade which currently comprises most Australian Army Reserve units located in Queensland. The Brigade was first formed in early 1916 as part of the 3rd Division and saw action during World War I and World War II.-Brigade Structure:*Headquarters...
had continued their advance north from Tsimba Ridge in April–May, clearing up to the Soraken Peninsula
Soraken
Soraken is a village on the Soraken Peninsula on northwestern Bouganville. The Soraken copra plantation was setup by Choisel Plantations in January 1913 and a tramway system long was constructed. The railway is now is disrepair...
which was captured by the middle of the month. By the end of May, however, the Japanese fell back behind a series of fortified positions along the base of the Bonis Peninsula, and the Australian advance came to a halt.
In an effort to break this resistance and allow the northwards advance to continue, the Australians attempted to outflank the Japanese line of resistance by launching an amphibious landing at Porton Plantation
Battle of Porton Plantation
The Battle of Porton Plantation took place at Porton Plantation, near the village of Soraken on Bougainville Island, in the Solomon Islands archipelago during World War II...
on 8 June. The plan called for a reinforced company
Company (military unit)
A company is a military unit, typically consisting of 80–225 soldiers and usually commanded by a Captain, Major or Commandant. Most companies are formed of three to five platoons although the exact number may vary by country, unit type, and structure...
from the 31st/51st Battalion
31st/51st Battalion (Australia)
The 31st/51st Battalion was an infantry battalion of the Australian Army, which served during World War II. Raised for service as part of the Militia in 1943 through the amalgamation of two previously existing battalions, the 31st/51st Battalion undertook garrison duties in Dutch New Guinea in...
to land behind the Japanese positions and attack from the west, while the main force consisting of the remainder of the 31st/51st Battalion and the 26th Battalion attempted to break through from the south. Due to poor planning, inadequate resources and strong Japanese defence, however, the landing failed at considerable cost to Australians, and as their efforts turned towards effecting a withdrawal from the beachhead and rescuing the stranded men, the attempt by the main force to break through from Ratsua also failed as tired troops came up against strong Japanese defensive positions.
Battle
Following the failed landing by the Australians at Porton Plantation, the commander of the Australian II Corps, Lieutenant General Stanley SavigeStanley Savige
Lieutenant General Sir Stanley George Savige, KBE, CB, DSO, MC, ED , was an Australian Army soldier and officer who served in World War I and World War II, rising to the rank of lieutenant general....
, decided to focus the main effort of the Australian campaign upon driving south towards the Japanese garrison at Buin, where the bulk of the Japanese forces were holding out. In order to concentrate enough forces for the next phase of the operation, however, Savige decided that the 11th Brigade, which had been carrying the advance north, should be relieved so that it could be transferred to the south following a period of rest and reorganisation.
Nevertheless, there was still a need to maintain the pressure upon the Japanese in the north, and so the 23rd Brigade
23rd Brigade (Australia)
The 23rd Brigade was a brigade of the Australian Army. Formed in 1940 for service during the Second World War, the brigade was initially a formation of the Second Australian Imperial Force assigned to the 8th Division, however, after its subunits were captured by the Japanese in 1942 it was...
—which had been previously operating in the central sector after being transferred from garrison duty in the Outer Islands—was also given responsibility for the northern sector as well, relieving the 11th Brigade on 20 June. The brigade's commander—Brigadier Arnold Potts
Arnold Potts
Brigadier Arnold William Potts DSO, OBE, MC was an Australian grazier who served in the First World War and led 21st Brigade of the Second AIF during its defence of the Kokoda Trail during the Second World War...
—was charged with keeping the Japanese force bottled up on the Bonis Peninsula and to send out patrols towards the Buka Passage
Buka Passage
Buka Passage is a narrow strait that separates Buka Island from the northern part of Bougainville Island. A number of shipwrecks are located in the passage....
. Initially, Potts was only allowed to allocate one of his three battalion
Battalion
A battalion is a military unit of around 300–1,200 soldiers usually consisting of between two and seven companies and typically commanded by either a Lieutenant Colonel or a Colonel...
s—the 27th
27th Battalion (Australia)
The 27th Battalion was an infantry battalion of the Australian Army. It was initially raised in 1915 as part of the First Australian Imperial Force for service during World War I. During the conflict, the battalion saw action briefly at Gallipoli before later fighting on the Western Front between...
—for the task, as the other two—the 7th and 8th Battalions—were to remain in the central sector; however, after intelligence reports indicated that the Japanese forces in the northern sector were stronger than the Australians initially thought, he requested permission to transfer the 8th Battalion, along with a battery
Artillery battery
In military organizations, an artillery battery is a unit of guns, mortars, rockets or missiles so grouped in order to facilitate better battlefield communication and command and control, as well as to provide dispersion for its constituent gunnery crews and their systems...
of artillery from the 4th Field Regiment that was to be based on the Soraken Peninsula. Due to the requirements of the advance to the south, however, no engineer or armoured support was initially available.
This request was approved, and by 28 June the two battalions and their supporting artillery were assembled; the 8th on the left, or western side of the peninsula, and the 27th on the right, with the artillery based on the Soraken Peninsula. The two battalions sent fighting patrols forward, however, due to the dense terrain, the Australian line of communication
Line of communication
A line of communication is the route that connects an operating military unit with its supply base. Supplies and reinforcements are transported along the line of communication. Therefore, a secure and open line of communication is vital for any military force to continue to operate effectively...
was quite long and the infantry spread out over a very wide area—with each battalion occupying a 4000 yards (3,657.6 m) front, which was twice the normal standard—security of their rear areas became an issue as the Japanese took the opportunity to disrupt the Australian logistic efforts, conducting ambushes, cutting communications and planting mines
Land mine
A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....
along the tracks. As the ambushes increased and casualties mounted, forward movement came to a halt, and by 21 July, the 27th Battalion reported having lost 10 men killed and 36 wounded without having gained any ground.
In light of this failure, the Australian brigade commander requested further resources to undertake a full scale offensive aimed at clearing the Japanese from the peninsula. This request was passed up to corps-level, however, there it was denied as Savige could not afford to release assets that were being used in the drive south. Under pressure to keep casualties to a minimum due to criticism in the media in Australia, Potts formulated a plan to withdraw the 27th Battalion from the right flank and to instead concentrate his forces on the left flank along a 3000 yd (2,743.2 m) front around the plantation at Buoi, to the north of Ratsua. Savige agreed to this on 22 July and the following day the 8th Battalion launched an attack against a feature known to them as "Commo Ridge", where it was believed that the Japanese were attempting to set up a forward position. The attack went in after a preliminary attack from the air, with one company
Company (military unit)
A company is a military unit, typically consisting of 80–225 soldiers and usually commanded by a Captain, Major or Commandant. Most companies are formed of three to five platoons although the exact number may vary by country, unit type, and structure...
attacking with two Matilda tanks from the 2/4th Armoured Regiment
2/4th Armoured Regiment (Australia)
The 2/4th Armoured Regiment was an armoured regiment of the Australian Army, which served during World War II. The regiment was formed in November 1942 as part of the Second Australian Imperial Force by amalgamating a number of previously existing armoured units and was disbanded in September 1946...
in support. Although the airstrike had been largely ineffective and both of the tanks struggled to cross the "swampy ground", the direct fire support provided by the tanks proved decisive and the Australians took the position with in 20 minutes, killing 12 Japanese.
On 24 July, the 8th Battalion launched another attack with two platoon
Platoon
A platoon is a military unit typically composed of two to four sections or squads and containing 16 to 50 soldiers. Platoons are organized into a company, which typically consists of three, four or five platoons. A platoon is typically the smallest military unit led by a commissioned officer—the...
s assaulting the Japanese position known as "Base 5". Prior to the assault, over 900 artillery shells and mortar bombs were brought down on the Japanese positions in an effort to prepare the position for the attack, however, this proved ineffective against well entrenched positions. The Australians reached their first objective, which was a small ridge in front of the main Japanese position, however, shortly after they began receiving effective fire from concealed positions which killed two men and wounded another in the forward section
Section (military unit)
A section is a small military unit in some armies. In many armies, it is a squad of seven to twelve soldiers. However in France and armies based on the French model, it is the sub-division of a company .-Australian Army:...
, pinning it in place.
Attempts to outflank the bunkers were answered with heavy fire from a medium machine gun and another man was killed and three more wounded. As the attack began to falter, one of the wounded, a 20-year-old private
Private (rank)
A Private is a soldier of the lowest military rank .In modern military parlance, 'Private' is shortened to 'Pte' in the United Kingdom and other Commonwealth countries and to 'Pvt.' in the United States.Notably both Sir Fitzroy MacLean and Enoch Powell are examples of, rare, rapid career...
, Frank Partridge
Frank John Partridge
Frank John Partridge VC was an Australian recipient of the Victoria Cross, a farmer and a television quiz champion.-Early life:Partridge was born at Grafton, New South Wales...
, who had been injured in the arm and thigh, braved the heavy fire that was being put down towards him and gathered the Bren light machine gun from the man who had been killed. After pouring suppressing fire onto the bunker he discarded the Bren and regathered his rifle, he then rushed towards the bunker with a grenade
Grenade
A grenade is a small explosive device that is projected a safe distance away by its user. Soldiers called grenadiers specialize in the use of grenades. The term hand grenade refers any grenade designed to be hand thrown. Grenade Launchers are firearms designed to fire explosive projectile grenades...
, killing its occupants. Partridge's actions reinvigorated the attack and allowed the Australians to take the second Japanese position. After the wounded were recovered, however, they withdrew having lost three men killed and five wounded. Against this eight Japanese were confirmed to have been killed. For his actions during the attack on 24 July, Partridge was awarded the Victoria Cross
Victoria Cross
The Victoria Cross is the highest military decoration awarded for valour "in the face of the enemy" to members of the armed forces of various Commonwealth countries, and previous British Empire territories....
, the British Commonwealth's highest military decoration. He was the last Australian to be awarded the medal during the Second World War, and was also the youngest.
Elsewhere, the Australians continued to mount patrols. On 2 August, a patrol from the 27th Battalion was sent out along the Ruri Bay Road in company with two tanks that were to act as their direct fire support. The Japanese were still active in the area, however, and had mined the road with a 500 lb (226.8 kg) bomb which they had rigged to be detonated remotely. The Australian patrol triggered the device and the resulting explosion killed three men in one of the tanks and wounded eight infantrymen following behind. On 5 August, the Australians reoccupied the position at Base 5 after encountering only slight resistance and subsequently named it "Part Ridge". After exploiting the position, it was discovered that the Japanese had built over 60 bunkers in the area, and subsequently they were withdrawn from the ridge again.
Aftermath
Atomic bombings of Hiroshima and Nagasaki
During the final stages of World War II in 1945, the United States conducted two atomic bombings against the cities of Hiroshima and Nagasaki in Japan, the first on August 6, 1945, and the second on August 9, 1945. These two events are the only use of nuclear weapons in war to date.For six months...
, the order to cease offensive combat operations on Bougainville was passed to all Australian units. Three days later, on 15 August, the Japanese Emperor Hirohito
Hirohito
, posthumously in Japan officially called Emperor Shōwa or , was the 124th Emperor of Japan according to the traditional order, reigning from December 25, 1926, until his death in 1989. Although better known outside of Japan by his personal name Hirohito, in Japan he is now referred to...
publicly announced Japan's unconditional surrender
Gyokuon-hoso
The , lit. "Jewel Voice Broadcast", was the radio broadcast in which Japanese emperor Hirohito read out the , announcing to the Japanese people that the Japanese Government had accepted the Potsdam Declaration demanding the unconditional surrender of the Japanese military at the end of World War II...
, effectively bringing about an end to the war. On 18 August, in the southern sector of the island the Japanese commander, General Masatane Kanda
Masatane Kanda
-Notes:...
, dispatched an envoy across the swollen Mivo River to begin negotiations with the Australians for the surrender of the over 23,000 Japanese soldiers left on the island, bringing about an end to the campaign. Throughout the course of the fighting on Bougainville from November 1944 to August 1945, 526 Australians were killed, while a further 1,572 were wounded. It is believed that 8,500 Japanese were killed in action, while a further 9,800 had died from disease during this same period.