The Battle of Wau, 29 January – 4 February 1943, was a battle in the New Guinea campaign of World War II. Forces of the Empire of Japan sailed from Rabaul and crossed the Solomon Sea and, despite Allied air attacks, successfully reached Lae, where they disembarked. Japanese troops then advanced overland on Wau, an Australian base that potentially threatened the Japanese positions at Salamaua and Lae. A race developed between the Japanese moving overland, hampered by the terrain, and the Australians, moving by air, hampered by the weather. By the time the Japanese reached the Wau area after a trek over the mountains, the Australian defenders had been greatly reinforced by air. In the battle that followed, despite achieving tactical surprise by approaching from an unexpected direction, the Japanese attackers were unable to capture Wau.
Background.
Geography.
Wau is a town in New Guinea, in the province of Morobe situated at one end of the Wau-Bulolo Valley. It was the site of a gold rush during the 1920s and 1930s. Gold prospectors arrived at the coast at Salamaua and struggled inland along the Black Cat Track. The miners partially cleared the area and built houses and workshops, and established a water supply and an electricity grid. They constructed the aerodromes at Wau and Bulolo which were the primary means of reaching the Wau-Bulolo Valley. Wau aerodrome was a rough Kunai grass airstrip in length with a 10 per cent slope heading directly for Mount Kaindi. Aircraft could approach from the north east only, landing uphill and taking off downhill. The mountain at the end of the runway prevented second attempts at landing and precluded extension of the strip. Pilots had to manoeuvre Dakotas under clouds and through dangerous passes, "dodging a peak here and cloud there", landing at high speeds. This required good visibility, but the weather over Owen Stanley Range was characterised by frequent storms, vertical drafts, and mists which rose from the jungle floor. The first landing at Wau was made by Ernest Mustard in his De Havilland DH.37 on 19 April 1927. Osmar White, who reached Wau in June 1942, wrote:
 ;templatestyles src="Template:Blockquote/styles.css" / ;[Wau and Bulolo] were towns built sole by virtue of man's conquest of the air. Every nail, sheet of iron, weatherboard, spot of paint, pane of glass, crock, wire or sheet of paper was carried in by air at freight rates between 4d and 1/5d per pound. The wrecked trucks that now dotted the highways, rusted out and twisted by fire, were brought in by air. The billiard tables at the hotels were brought in by air. Easy chairs, refrigerators, bathtubs, stoves, dynamos, linoleum, carpets, garden statuary, even great mining dredges, bulldozers and power shovels—all were brought in by air, and this in a decade when most people in Australia were still thinking it adventurous to take a five-minute joy ride over an airfield.
Kanga Force.
After the war with Japan began, Wau became an evacuation centre, receiving refugees from Lae and Salamaua. Non-native women and children were evacuated while men of military age were called up for service in the New Guinea Volunteer Rifles, the local militia unit. Initially, civilians were evacuated by civilian aircraft but as the Japanese drew closer—bombing Wau on 23 January 1942—it became too dangerous to fly without fighter escort, which was unavailable. This left some 250 European and Asian men stranded. These refugees made a hazardous journey over the Owen Stanley Range on foot by way of Kudjeru and Tekadu to Bulldog, a disused mining settlement where there was an aerodrome, and thence down the Lakekamu River to the sea.
With the feasibility of the route thus demonstrated, New Guinea Force decided to establish a line of communications to Wau via the Bulldog Track. A platoon of the 1st Independent Company left Port Moresby in the schooner "Royal Endeavour" and traversed the route, joining the men of the New Guinea Volunteer Rifles holding the Wau area. This was the beginning of what became Kanga Force on 23 April 1942. On 22 May, the 21st Troop Carrier Squadron USAAF flew in commandos of the 2/5th Independent Company to join Kanga Force. The 2/7th Independent Company followed in October 1942.
Supplies could be flown into Wau if fighter cover was available. On 5 September, 12 planeloads of supplies were dropped at Kudjeru. To economise on scarce transport aircraft, air transport was supplemented by an overland route. Supplies were shipped to the mouth of the Lakekamu in luggers, transported up the river to Bulldog in launches or powered dugout canoes, and then carried over the Bulldog Track by native carriers.
Strategy.
Kanga Force achieved one notable success, in a raid on Salamaua in June 1942, but "apart from that they had done little to harass the Japanese at their Salamaua and Lae bases." They had however managed to threaten the Japanese without provoking them into an offensive against Wau at a time when the Allies did not have the resources to reinforce Kanga Force, and they had provided valuable information. Wau occupied an important place in the strategy of the Commander, Allied Land Forces, South West Pacific Area, General Sir Thomas Blamey, who was concurrently commanding New Guinea Force from Port Moresby. At the time, the Japanese held air superiority over the Solomon Sea, precluding airborne or seaborne operations against the Japanese base at Lae. Blamey therefore decided that he would have to capture Lae with a land campaign. The Bulldog Track would be upgraded to a highway capable of carrying trucks and tanks that could support a division that would advance overland on Lae.
Lieutenant General Hitoshi Imamura, the commander of the Japanese Eighth Area Army at Rabaul, correctly deduced his opponent's intentions and the strength of Kanga Force and resolved to head off the danger to Lae. He ordered Lieutenant General Hatazō Adachi's Eighteenth Army to secure "important areas to the west of Lae and Salamaua". On 29 December 1942, Adachi ordered the 102nd Infantry Regiment and other units under the command of Major General Toru Okabe, the commander of the infantry group of the 51st Division, to move from Rabaul to Lae and then immediately advance inland to capture Wau. Okabe's force was known as the Okabe Detachment.
Imamura was up against a resourceful, resolute and aggressive opponent, who also had access to good intelligence. Allied Ultra codebreakers were reading the Japanese shipping codes, and, by 3 January 1943, Allied commanders knew in advance about the force that Adachi was planning to send from Rabaul to Lae, although they did not know the force's ultimate destination. Blamey chose not to wait for this to become clear, but immediately ordered the 17th Infantry Brigade to move from Milne Bay to Wau on 4 January 1943. Its commander—Brigadier Murray Moten—was ordered to assume command of Kanga Force and defend Wau.
Prelude.
The Commander, Allied Air Forces, South West Pacific Area, Lieutenant General George Kenney, ordered his bomber commander, Brigadier General Kenneth Walker, to carry out a full-scale dawn bombing attack on the shipping in Rabaul Harbour before it could depart. Walker demurred; his bombers would have difficulty making their rendezvous if they had to leave Port Moresby at night. He recommended a noon attack instead. Kenney acknowledged Walker's concerns but was insistent; he preferred bombers out of formation to bombers shot down by the enemy fighters that were sure to intercept a daylight attack. Inclement weather precluded participation by bombers from Australia, so all that was available were the aircraft on hand in Papua: six B-17s and six B-24s. In spite of Kenney's orders, Walker attacked Rabaul Harbour at noon on 5 January, and encountered heavy flak and continuous fighter attacks. Forty and 24 bombs were dropped from . The formation claimed hits on nine ships, totalling 50,000 tons. Two B-17s were shot down, including the one carrying Walker, who was posthumously awarded the Medal of Honor. After the war, JANAC confirmed the sinking of only one Japanese merchant ship, the 5,833-ton "Keifuku Maru". Two other ships were damaged, as was the destroyer .
On 6 January, the Japanese convoy carrying Okabe's force set out for Lae from Rabaul. Forewarned by Ultra, USAAF and RAAF aircraft spotted, shadowed and attacked the convoy, which was shielded by low clouds and Japanese fighters. The Allies claimed to have shot down 69 Japanese aircraft for the loss of 10 of their own. A P-38 pilot, First Lieutenant Richard Bong claimed three, becoming an ace. A RAAF Catalina of No. 11 Squadron RAAF under the command of Flight Lieutenant David Vernon made a night bombing attack on the convoy which sank the transport "Nichiryu Maru". Destroyers rescued 739 of the 1,100 troops on board, but the ship took with it all of Okabe's medical supplies. Another transport, "Myoko Maru", was so badly damaged at Lae by USAAF B-25s that it had to be beached. Nonetheless, the convoy succeeded in reaching Lae on 7 January and landing about 4,000 troops. In all, the Allied Air Forces flew 416 sorties.
Between 10 and 16 January, the Okabe Detachment moved down the coast in barges to Salamaua, where it assembled and completed its preparations for the attack on Wau. On 16 January, the Japanese encountered a platoon of the 2/7th Independent Company under Captain Geoffrey Bowen. A brief action followed in which Bowen was killed, and the Australians retreated back to Skindewai. However, instead of pursuing them, Okabe chose to advance on Wau down an old and seldom used track running through difficult country parallel to the Black Cat Track, and the two sides lost contact. Okabe thereby disguised the strength and objective of his force, and took the Australians by surprise. It was necessary to cross Komiatum Hill, advance to Mubo, and then take the track westward. This route was chosen so as to avoid observation from Allied aircraft in the daytime as they cut their way into the jungle. The mountain range east of Wau was about high and not particularly difficult to cross, but in parts there were no tracks. These had to be prepared without being spotted by the Allied aircraft. As the troops had to carry their food, ammunition and equipment on their backs, the advance was difficult and took longer than anticipated. Eventually they reached a peak from which they were able to look down on the Wau-Bulolo Valley. By this time, food was running short. The commander of the Okabe Detachment, pointing at the Wau village, gave the order to attack: "We are short of food—let us quickly capture Wau and get food from the enemy!" However, the movement through such dense jungle caused his units to lose touch with each other. The resulting attack was delivered piecemeal, without sufficient preparation.
Meanwhile, the first group of the 17th Infantry Brigade—the 2/6th Infantry Battalion—had embarked for Port Moresby on 9 January 1943. The rest of the battalion followed over the next two nights. The 2/7th Infantry Battalion departed Milne Bay on the Army transport on 13 January and the 2/5th on the next day. The prospects of beating the Japanese to Wau did not look good. At this time, there were only 28 Dakotas in New Guinea, in three understrength squadrons, the 6th, 21st and 33rd Troop Carrier Squadrons of the US 374th Troop Carrier Group. These had to be shared with the Buna-Gona front, so each combat area had 14 planes allocated to it, which worked out to 10 aircraft available per day for each. A Dakota could carry 27 passengers or of freight. Moving an infantry battalion required 60 plane loads; moving a brigade group required 361 plane loads. Between 10 and 19 January, the 2/6th Infantry Battalion was flown in from Port Moresby to reinforce Kanga Force. In the process, there were three crashes. Poor flying weather forced many aircraft to return without landing. Brigadier Moten was twice forced to return to Port Moresby before reaching Wau on the third attempt. Bad weather continued over the following week, limiting air operations and sometimes precluding them entirely. Part of the 2/5th Infantry Battalion arrived on 27 January.
Battle.
Standing in the way of Okabe's advance was A Company of the 2/6th Infantry Battalion under Captain W. H. Sherlock. Okabe ordered an all-out attack on Sherlock's position on 28 January. Sherlock was forced from his position and retreated onto a nearby spur. For much