Written by Geoff Bell with kind assistance from Peter Salter

These notes have been prepared to provide additional background on 2/20th Battalion operations in Singapore in 1942, and hopefully to give people who have not experienced military operations a better understanding of the context in which the Battalion fought the Japanese onslaught in early 1942. People wishing to get a fuller picture of the Battalion’s action should read the Battalion history “Singapore and Beyond” by Don Wall.

The author accepts full responsibility for the content of the notes.

Any errors or omissions are entirely the fault of the author.

Singapore’s Geography in 1942

  • Singapore is a small island – only about 42km east to west and 22km north to south. There is little room to mount an effective military defence of the island against an attack from the Malay peninsula.
  • There is a very narrow strait separating Singapore fro the peninsula. The strait is at its narrowest point in the northwest of the island.
  • The Singapore shoreline was somewhat different in 1942 than it is now. There were many mangrove-lined creeks and rivers, which provided excellent opportunities for the Japanese to use their favourite tactic of infiltrating forces between and behind their opposition.
  • Tengah Airfield, located in the northwest of the island, was one of Singapore’s main airfields at the time. Although there were no Allied aircraft operating from it in February 1942, it would have been a high priority objective for the Japanese, who would have wanted access to an airfield as close as possible to the action. Aircraft operating form such an airfield could spend more time attacking Allied forces on the island and elsewhere, rather than transiting from airfields on the peninsula.
  • Singapore’s main water supply reservoirs were located in the north of the island. These would have been another major objective for the Japanese.
  • The vegetation on Singapore in 1942 included rubber plantations, jungle and extensive mangrove swamps. Vegetation was generally quite thick, which severely restricted observation and fields of fire for both sides, but offered greater advantage to the infiltrating Japanese.
  • There were far fewer buildings than there are now, and the civilian population was much smaller. Rural land and jungle covered much of the island.

Japanese Plan for the Attack on Singapore

  • The Japanese commander, General Yamashita, planned his final assault on Singapore knowing that he was running short of weapons, ammunition, fuel and food. Logistics logjams existed along his supply lines and his army was facing the serious prospect of starvation because food supplies were not getting through.
  • Yamashita’s dilemma was that if he were strike at Singapore too quickly, his lack of supplies might mean defeat. However, if he waited in the hope of accumulating additional supplies, he would run the risk of the Allies being reinforced. His fear was that the fighting might degenerate into a long battle of attrition. If that happened, the odds would be heavily stacked against him.
  • The Japanese 25th Army has sustained significant casualties during the Malaya campaign and could only field 30,000 frontline infantrymen. Japanese intelligence estimates had the defending forces strength at 40,000 when they were actually more than twice that number.
  • Based on this inaccurate intelligence, Yamashita decided on a massive gamble. This involved deceiving the Allies by creating the impression that the Japanese still had massive firepower. Yamashita later admitted “My attack on Singapore was a bluff. I had 30,000 men and was outnumbered more than three to one (as it turned out!). I was very frightened all the time that the British would discover our numerical weakness and lack of supplies and force me into disastrous street fighting.”


A primary doctrine of the Japanese Army was always to try to gain and maintain the initiative over their opposition – keeping them “on the hop”, creating confusion and reducing the support available from adjacent defenders. This proved successful as they advanced down the Malay peninsula, even though the Allies had caused significant Japanese casualties at places like Gemas, Muar, Nithsdale Estate and north of the Mersing River.

Specific tactics used by the Japanese included:

  • Infiltration of substantial forces using small groups to get between Allied defensive positions;
  • Attacks by means of outflanking or pincer movements rather than frontal assaults (although the latter were used to hold Allied forces in position whilst outflanking movements were done);
  • Finding and exploiting boundaries between defending organisations, thus helping to create confusion and making defensive coordination very difficult;
  • Placement of blocking forces behind Allied positions to create difficulties during withdrawal;
  • Aggressive use of tanks, mortars, artillery and aircraft in support of infantry;
  • Widespread use of snipers;
  • Substantial pre-attack reconnaissance operations; and
  • Use of all available forms of transport to move troops and supplies quickly to where they were needed most. The Japanese tactical doctrine emphasised reinforcement of the places on the battlefield at which they already had success.

Attack on Singapore

  • Before they could use these tactics, the Japanese first had to cross the Strait of Johore. They very sensibly chose the narrowest part near the northwest of the island. Three battle-hardened divisions (5th, 18th and Guards), supported by tanks and artillery, attacked the 8th Australian Division, which had had no time to recover from intense fighting in Malaya. [Please refer to the final page for a brief explanation of military organisations.] In choosing the narrowest part of the strait, the Japanese reduced the amount of time the Australian had to react, as well as minimising the time their troops would be exposed as they crossed the open water.
  • The main Japanese attack was made by the 5th and 18th Divisions west of the Kranji River towards positions held by 22nd Brigade, which included 2/20th Battalion as the forward battalion. This attack aimed to outflank the entire British defensive position on Singapore.
  • The Guards Division attacked to the east of the Kranji River towards positions held by 27th Brigade, with a view to securing the Causeway approaches and to threaten Singapore’s water supply reservoirs.
  • The Japanese also made a diversionary attack towards the northeast of the island. The Allied High Command was taken in by this attack, committing resources to defend against it at the expense of the defence against the main attack in the northwest sector. This allowed the Japanese much greater freedom of manoeuvre in the early stages, and they were able to get between and behind the 22nd Brigade defenders, thus opening up the left flank of the island’s entire defence.
  • Scale of the Japanese Attack

The scale of the Japanese attack on the northwest sector can be judged from some of the statistics:

  • There were sixteen Japanese infantry battalions attacking the northwest sector; against them were just three understrength Australian battalions.
  • The Japanese fired some 80,000 artillery shells onto the island prior to and during their attack. These shells were fired by about 30 artillery batteries, employing field guns and 60 heavy mortars. In contrast, the Australians had just three artillery batteries in support. People who experienced artillery bombardments on the Western Front in WW1 expressed the opinion that the Japanese shelling was more intense than anything they had known before.
  • The Japanese also had complete control of the air. This meant they could observe the Australian positions with impunity, and could bomb and strafe rear echelons and supply lines as well as front lines. This impacted of this on the Australian’s ability to manoeuvre and fight should not be underestimated.

Overall Allied Operational Plan

Preparations (or lack thereof)

  • Six weeks before the fall of Malaya, the Chief Engineer of Malaya Command, Brigadier Ivan Simson, attempted to persuade the commander, Lt-General Percival, to start building defensive positions on Singapore.
  • Simson argued for a crash program to prepare beach defences along the island’s northern shoreline, together with a series of fixed positions in depth to cover the most likely Japanese objectives. His advice was ignored by Percival who commented that: “Defences are bad for morale – for both troops and civilians.”
  • Several weeks were wasted before work was eventually started on building the island’s defences. Unfortunately, Percival ordered this to occur in the northeast, leaving the northwest exposed and under-resourced.

A Doomed Defence

  • Percival’s plan was to divide Singapore into three main defensive sectors: Southern, Northern and Western. Australian Major-General Gordon Bennett was given command of the Western Sector, with one Indian and two Australian brigades at his disposal. The Western Sector frontline ran from the just east of the Causeway right around to the Jurong River mouth, a distance of 28km. This was an extraordinarily large distance for these three brigades to cover.
  • The Allied High Command in Singapore clearly misappreciated Japanese operational intentions. They also seem to have failed to take adequate account of the geography of the island, and the state of the troops who had just fought the Japanese down through the Malay peninsula.
  • This misappreciation resulted in the placement of fresh Allied troops in the Northern Sector, together with the priority of defensive effort. The Allied High Command appeared to put all its eggs in the one basket, and ultimately got it wrong.
  • No defensive preparations had been made for the Australians prior to them occupying their positions in the northwest – ie, there were no minefields laid or barbed wire and other obstacles erected. By the time the Australians took up their positions, it was too late to do anything much about it. This certainly didn’t stop the Australians doing what they could with limited resources, and requesting additional defensive stores such as mines, barbed wire and the like. However, these requests were often ignored or refused outright. [NB: As POWs, the Australians had the galling task of loading substantial amounts of unused defensive stores on to Japanese ships for use elsewhere.

2/20 Battalion Operations

This short description of the action in the 2/20th area of operations (AO) is written to provide an overview of what it might have been like for the soldiers who fought there. Please see "Singapore and Beyond" for a full explanation of the fighting.

Organisation and General Dispositions

  • 22nd Brigade was reorganised in Singapore to comprise 2/18th, 2/19th and 2/20th Battalions, supported by 2/15th Field Regiment [the artillery equivalent of an infantry battalion], and elements of the 4th Anti-Tank Regiment [also equivalent to an infantry battalion] and 2/4th Machine Gun Battalion. The brigade was only at about half strength (approximately 2500 troops), its battalions having suffered substantial casualties in Malaya. Despite this it had been given the impossible task of defending almost 15km of the front line. 2/20th was responsible for about half of this frontage, even though it was directly opposite the main Japanese forces which could be seen concentrating across the Strait of Johore.
  • 2/20th had responsibility for about 25 square kilometres of the AO. The Battalion had just 850 men to defend this huge area, including about 100 who were reinforcements with little training and no experience of intense military operations. During the first two days of the battle, some 400 of these people were either killed or wounded.

Company Deployments

  • A Company was deployed to defend the eastern or right hand sector of the Battalion AO, between the Buloh Besar and Kranji Rivers. On its left was D Company.
  • B Company was in reserve near Battalion HQ, but was soon in the thick of the fighting.
  • C Company was on the left of the Battalion AO, with 2/18th Battalion on its left and D Company on its right.
  • D Company was in the centre of the Battalion frontline, with A Company on its right and C Company on its left.
  • The forward companies (A, B & D) all overlooked the Strait of Johore.
  • Specialist battalion troops such a Pioneers, Signals, Machinegun Carriers, Anti-aircraft, Mortars, Transport, Medical etc were operating throughout the AO, as were supporting forces such as artillery observers, 13 Platoon 2/4th MG Battalion and Dalforce (a unit comprised mainly of local people) was deployed in the A Company area.
  • The companies were deployed into dispersed platoon positions. Although the platoons then deployed into smaller groups called sections to defend their allocated area, there were still some large gaps in the defence. The area allocated to the Battalion was simply too great.
  • This meant there were few interlocking arcs of fire between positions, resulting in each small position having to fight essentially on its own – a sure recipe for disaster against a well trained enemy using infiltration tactics.

Outline Sequence of Events

  • 31 January 2/20th occupies it AO.
  • 1-7 February Defensive preparations undertaken together with limited patrolling across the Strait. Japanese reconnaissance of Singapore underway.
  • 8 February Japanese assault commences after huge bombardment to “soften up” the defences. Japanese beachhead firmly established by days end.
  • 8-9 February Main battle.
  • 10-15 February What’s left of 22nd Brigade withdraws to the area around Bukit Timah in the centre of the island. Regrouping occurs (eg, Merritt Force and X Battalion). Operations continue in the Ulu Padang/Holland Road area until the surrender.

Nature of the Fighting

  • What would fighting have been like in the 2/20th AO? The notes below seek merely to give readers a flavour of the operations, drawing on the author’s experience as an Army officer. Again, people should refer the Battalion history, “Singapore and Beyond”, or if possible speak to those who were there, in order to get a fuller picture of what the battle was really like.
  • There would have been an incredible amount of noise caused by artillery, mortars, hand grenades and small arms fire.
  • Fighting was done in small groups, which tended to increase the sense of isolation that would have been felt at times by many troops during the battle. The area the battalion had to cover was simply too great and inevitably there were large gaps between defensive positions. The Japanese exploited these gaps very successfully.
  • The initial fighting was done from prepared positions, either trenches dug into the ground, or strong points built above it where the water table was too high. These fortifications provided some protection against the bombardment and direct attack with small arms and grenades. However, once the Japanese got between and behind the defence, the battle became very fluid. This meant that much of the fighting after the first assault was conducted in the open without any protection, and in a situation where the Australians were heavily outnumbered by an enemy that had the initiative.
  • There would have been great confusion at times, caused by lack of communications as well as the disruption of the chain of command as a result of many officers and non-commissioned offers being killed or wounded.
  • At times, the smoke and vegetation would have made it very difficult for the defenders to see their enemy. Also, the fighting continued through the night when the only light was from flares and fires burning in the area.
  • Operations were continuous – there would have been little chance for rest, and the men would have been exhausted and hungry.
  • The enemy was all around – there was nowhere in the AO that could be considered safe.
  • Many people were killed or wounded – some 400 2/20th soldiers became casualties during the initial part of the battle. Treatment and evacuation of casualties was done under extremely difficult conditions.
  • Much of the fighting would have been done at close quarters and would often have involved hand-to-hand combat.
  • It is clear from “Singapore and Beyond” and similar histories that there were many acts of heroism by the Australians in the face of overwhelming odds. Unfortunately, it seems that the vast majority of these acts went officially unrecognised.

Brief Explanation of Military Organisations

This section seeks to provide a very brief explanation of military organisations, to help the non-military reader gain a better understanding as they undertake further research.

Divisions are the largest army organisations that fight tactically. They are made up of many smaller building blocks which also have a fighting role, or are in support of the fighting troops.

The most basic element of any army organisation is the infantry section, comprising about 8-10 men, with a machine gun included in its weapon mix. Other army combat elements such as armour (tanks), artillery, engineers etc are also organised using a building block approach.

Different armies have different views on how best to organise their tactical forces. Most base their structure on “threes”, although some use “fours”. Army organisations are thus built as follows:

  • Three sections make up a platoon, commanded by a lieutenant who is normally supported by a sergeant.
  • Three (or in Australia’s case at the time, four) platoons make up a company, commanded a major or sometimes a captain, who is supported by a small headquarters and some supporting elements. There could be between 120-150 troops in a company at full strength.
  • Three (or in Australia’s case, four) companies make up a battalion, commanded by a lieutenant colonel, who is supported by a headquarters with staff officers who provide operations, logistics, intelligence and artillery advice to the CO. The battalion also has inherent specialist elements including mortars, pioneers, medical, signals, carriers, and logistics, administration and transport. There could be between 800-1000 troops in a battalion at full strength. The battalion may also be allocated various external support elements from the brigade or regiment, depending on the circumstances. These could include tanks, artillery, heavy machine guns, anti-tank guns, engineers and reconnaissance elements.
  • Three battalions make up a regiment in the Japanese Army, commanded by a colonel, or a brigade in the Australian Army, commanded by a brigadier. It is at this level that tactical operations and logistics support are often controlled, coordinated and directed. Brigades or regiments have a strength of between 3000-5000 troops, depending on their structure. [NB: the term "regiment" is used in the Australian Army to identify battalion-sized supporting elements such as artillery, armour, engineers, signals, anti-tank etc.]
  • Three brigades (or regiments in the Japanese Army) make up a division, commanded by a major general, who is supported by a substantial staff responsible for the overall coordination of the tactical battle. With additional supporting elements, a division could have an overall strength of between 10,000-15,000 troops.