Battle of Pearl Ridge
Encyclopedia
The Battle of Pearl Ridge (30–31 December 1944) was a battle of the Second World War fought between Australia
n and Japanese
forces on Bougainville Island
. Part of the wider Bougainville Campaign, the battle took place in the central sector of the island, shortly after the Australians had taken over responsibility from the Americans. Believing that the ridge was held by less than a company
of Japanese, on 30 December the Australian 25th Battalion launched a four-pronged attacked the ridge. The defending force, however, had been greatly reinforced and was closer to a battalion
in strength. After being held up on the right of their advance, the Australians dug in overnight and repulsed a strong Japanese counterattack before resuming the attack on 31 December. By late in the afternoon, the Japanese had been swept off the ridge.
s from the Australian II Corps
took over responsibility for Bougainville from the divisions of US XIV Corps that had been stationed there previously. At the time, it was believed that the Japanese forces on the island numbered around 17,500 men—although intelligence reports and estimates on this matter varied greatly and indeed after the war it was found that there had been more than 40,000 at the time—and although understrength the Allies believed that the Japanese formations in the area were still capable of carrying out effective combat operations. In order to counter this, it was decided that the Australian II Corps, consisting of the 3rd Division and the 11th Brigade
would go on the offensive and a three pronged campaign was planned in the northern, central and southern sectors of the island.
Initially, the 7th Brigade was given responsibility for the central sector, and in November it began operations to clear the Japanese from the high features in the sector. On 23 November, the Australian 9th Battalion captured a Japanese outpost on a feature known as Little George, before taking part in the capture of Artillery Hill in mid December.
Shortly after this, the Australian 25th Battalion—under Lieutenant Colonel John McKinna—relieved the 9th Battalion at Artillery Hill and began patrolling operations towards the Japanese position on Pearl Ridge, a feature which due to its height offered commanding views of the entire island.
and machine gun
fire with four companies
advancing across a 1000 yd (914.4 m) frontage stretching across the ridge. Unbeknown to the Australians, however, the two companies from the 81st Infantry Regiment had been reinforced by 550 men from the Japanese 38th Independent Mixed Brigade under Major General Kesao Kijima and they had heavily fortified the ridge with up six artillery pieces and between 20–30 mortar
s. Although the left-most Australian company managed to reach the ridge, due to the terrain the company on the far right of the Australian line was forced into advancing across a narrow razorback only 12 ft (3.7 m) wide, along which the Japanese were able to concentrate a significant amount of fire which prevented the Australians from moving forward.
As more artillery fire was brought down on the ridge in support of the attack, an made attempt was made to outflank the Japanese position in front of the razorback, although these too proved unsuccessful and after the Australians had suffered a number of casualties the attack on the right was called off and the company ordered to form a defensive position and await further orders. The Australian commander, McKinna, then ordered the two companies in the centre to dig in where they were, while the left most company, which had reached the Japanese track on the northeastern side of the ridge would also dig in and attempt to hold its position until daybreak. During the night the Japanese counter attacked. They were, however, repulsed and the following day the Australians resumed their attack. By late afternoon, the Japanese defenders had pulled back from the ridge, leaving the Australians in possession of it and with it a vantage point from where they could see from one side of Bougainville to the other.
During the course of the battle, the Australians lost 10 killed and 25 wounded, while 34 Japanese bodies were found around the position and one prisoner taken.
from where they could fire on Japanese positions under the control of forward observers on Pearl Ridge.
Due to the terrain around the ridge, many resources were used to bring in supplies and so in an effort to improve the Australian line of communication
s in the sector, engineers
from the 16th Field Company constructed a road using a bulldozer that had to haul itself up the ridge via a steel cable that was manhandled up to a point just below the ridge over the course of eight days.
After the war, the 25th Battalion was awarded the battle honour
of "Pearl Ridge" for the battle. Today this honour is maintained by the 25th/49th Battalion, Royal Queensland Regiment.
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 Japanese
Empire of Japan
The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...
forces on Bougainville Island
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...
. Part of the wider Bougainville Campaign, the battle took place in the central sector of the island, shortly after the Australians had taken over responsibility from the Americans. Believing that the ridge was held by less than a 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...
of Japanese, on 30 December the Australian 25th Battalion launched a four-pronged attacked the ridge. The defending force, however, had been greatly reinforced and was closer to a 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...
in strength. After being held up on the right of their advance, the Australians dug in overnight and repulsed a strong Japanese counterattack before resuming the attack on 31 December. By late in the afternoon, the Japanese had been swept off the ridge.
Background
Advanced Australian elements began arriving on Bougainville in September and by November–December 1944 four brigadeBrigade
A brigade is a major tactical military formation that is typically composed of two to five battalions, plus supporting elements depending on the era and nationality of a given army and could be perceived as an enlarged/reinforced regiment...
s from the Australian II Corps
Australian II Corps
The Australian II Corps was an Australian Army corps. II Corps was established in early 1942 to command Australian Army units deployed to protect the Sydney region and later commanded operational units in New Guinea, Bougainville and New Britain...
took over responsibility for Bougainville from the divisions of US XIV Corps that had been stationed there previously. At the time, it was believed that the Japanese forces on the island numbered around 17,500 men—although intelligence reports and estimates on this matter varied greatly and indeed after the war it was found that there had been more than 40,000 at the time—and although understrength the Allies believed that the Japanese formations in the area were still capable of carrying out effective combat operations. In order to counter this, it was decided that the Australian II Corps, consisting of the 3rd Division and 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...
would go on the offensive and a three pronged campaign was planned in the northern, central and southern sectors of the island.
Initially, the 7th Brigade was given responsibility for the central sector, and in November it began operations to clear the Japanese from the high features in the sector. On 23 November, the Australian 9th Battalion captured a Japanese outpost on a feature known as Little George, before taking part in the capture of Artillery Hill in mid December.
Shortly after this, the Australian 25th Battalion—under Lieutenant Colonel John McKinna—relieved the 9th Battalion at Artillery Hill and began patrolling operations towards the Japanese position on Pearl Ridge, a feature which due to its height offered commanding views of the entire island.
Battle
Believing that the ridge was held by two understrength companies from the Japanese 81st Infantry Regiment—approximately 80–90 men—it was decided to commit only a battalion to capture it. On the morning of 30 December, after 40 minutes of airstrikes, the 25th Battalion carried out an attack supported by artilleryArtillery
Originally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
and machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
fire with four companies
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...
advancing across a 1000 yd (914.4 m) frontage stretching across the ridge. Unbeknown to the Australians, however, the two companies from the 81st Infantry Regiment had been reinforced by 550 men from the Japanese 38th Independent Mixed Brigade under Major General Kesao Kijima and they had heavily fortified the ridge with up six artillery pieces and between 20–30 mortar
Mortar (weapon)
A mortar is an indirect fire weapon that fires explosive projectiles known as bombs at low velocities, short ranges, and high-arcing ballistic trajectories. It is typically muzzle-loading and has a barrel length less than 15 times its caliber....
s. Although the left-most Australian company managed to reach the ridge, due to the terrain the company on the far right of the Australian line was forced into advancing across a narrow razorback only 12 ft (3.7 m) wide, along which the Japanese were able to concentrate a significant amount of fire which prevented the Australians from moving forward.
As more artillery fire was brought down on the ridge in support of the attack, an made attempt was made to outflank the Japanese position in front of the razorback, although these too proved unsuccessful and after the Australians had suffered a number of casualties the attack on the right was called off and the company ordered to form a defensive position and await further orders. The Australian commander, McKinna, then ordered the two companies in the centre to dig in where they were, while the left most company, which had reached the Japanese track on the northeastern side of the ridge would also dig in and attempt to hold its position until daybreak. During the night the Japanese counter attacked. They were, however, repulsed and the following day the Australians resumed their attack. By late afternoon, the Japanese defenders had pulled back from the ridge, leaving the Australians in possession of it and with it a vantage point from where they could see from one side of Bougainville to the other.
During the course of the battle, the Australians lost 10 killed and 25 wounded, while 34 Japanese bodies were found around the position and one prisoner taken.
Aftermath
Following the battle of Pearl Ridge, the Australians launched a full scale offensive to counter the Japanese resistance on the island. As a result of this decision, the 7th Brigade was moved from the central sector to the southern sector, where the majority of the Japanese forces were located. The 11th Brigade then took control of both the central and northern sectors in order to free up troops for the main offensive in the south. The brigade maintained a battalion-group element on the ridge during this phase and carried out extensive patrols forward of the position, while artillery was brought up to the foot of the Laruma escarpmentEscarpment
An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...
from where they could fire on Japanese positions under the control of forward observers on Pearl Ridge.
Due to the terrain around the ridge, many resources were used to bring in supplies and so in an effort to improve 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...
s in the sector, engineers
Royal Australian Engineers
The Royal Australian Engineers is a corps of the Australian Army . The RAE is ranked fourth in seniority of the corps of the Australian Army, behind the Staff Cadets, Armoured and Artillery Corps...
from the 16th Field Company constructed a road using a bulldozer that had to haul itself up the ridge via a steel cable that was manhandled up to a point just below the ridge over the course of eight days.
After the war, the 25th Battalion was awarded the battle honour
Battle honour
A battle honour is an award of a right by a government or sovereign to a military unit to emblazon the name of a battle or operation on its flags , uniforms or other accessories where ornamentation is possible....
of "Pearl Ridge" for the battle. Today this honour is maintained by the 25th/49th Battalion, Royal Queensland Regiment.