Australian and Papuan troops advanced along the coast of the Huon Peninsula, using infantry, tanks, and air strikes against the Japanese positions, which were generally sited at creek crossings in the jungle.

The advancing infantry kept strictly within range of the supporting artillery, which was liberally employed in the early stages of the operation.

This had an important effect on the subsequent course of the war against Japan in the South West Pacific, as it permitted codebreakers in Australia and the United States to read Japanese Army messages on a much greater scale than previously.

This major intelligence windfall led to MacArthur accelerating the South West Pacific's timetable by over three months, starting with the Admiralty Islands campaign in February followed by the landings at Hollandia and Aitape in April far behind enemy lines.

[7] Lieutenant General Frank Berryman, the commander of Australian II Corps, now urged Wootten to commence a coastal advance to cut the Japanese supply lines and force Adachi to retreat from the Huon Peninsula if he were not already doing so.

[8] Early in October 1943, a special staff was established at II Corps Headquarters to study the Japanese supply system.

[13] When General Berryman saw Vice Admiral Thomas C. Kinkaid, the commander of the Allied Naval Forces, on 14 December, he made a point of congratulating him on the work his PT boats were doing.

[14] Lieutenant General Tsutomu Yoshihara, Chief of Staff of the Japanese Eighteenth Army recalled: At this time the air at 20th Division H.Q.

The troops, short of food and ammunition, were searching for vegetables left in the native gardens around them and were so hungry they were eating banana and pawpaw roots.

With no training, no equipment the captains and crews of these fishing boats braved the front line of the fighting and all the dangerous places, saying, "We are immortal.

[18] A secondary outflanking movement was made inland, over the higher ground, which was usually coral cliffs covered by kunai grass and rising as high as 4,000 ft (1,200 m).

Artillery guns were brought forward over the tracks or else were moved by Landing Craft Mechanised (LCMs) of the 532nd EBSR.

The monsoon caused rough seas that precluded the use of the small Landing Craft, Vehicle, Personnel (LCVPs) and restricted the operations of the larger LCMs.

[20] Wootten insisted that at least seven days' supplies be available in forward areas in case the weather prevented the LCMs from running.

A preliminary operation by the 22nd Infantry Battalion on 3 December 1943 secured a crossing area and a log bridge was constructed.

It resumed the next day, and the Japanese withdrew after an artillery bombardment, their orders being "while avoiding any decisive engagement" to "carry out successful resistance to try to delay the enemy advance".

[26] To support the attack on Lakona, the tanks had to cross a creek with steep coral banks, swollen by a torrential downpour.

While efforts were made to bring up a compressor, tanks fired into banks and holes were packed with explosives and detonated.

[27] On 20 December, aided by four Matilda tanks and 750 rounds from the 25-pounders, the 4th Infantry Brigade occupied the Fortification Point area.

General Blamey insisted that Christmas fare be available to all units, and extraordinary efforts were made to carry out his directive.

An Australian sapper checking the stream bed for booby traps with a metal detector discovered it, and it was dug up in the belief that it was a mine.

On 4 February 1944, Central Bureau codebreakers decrypted a thirteen-part message that laid out the decisions reached at a conference of high-ranking Japanese officers.

The 20th Infantry Brigade had lost 3 killed and 13 wounded, but 958 had been evacuated sick, mostly with malaria, and an epidemic of dengue had also taken its toll.

[3] The 8th Infantry Brigade, which had spent much of the war on garrison duty in Western Australia, began departing Cairns on 10 January.

[35] The original intention had been for it to go to Lae to relieve the 29th Infantry Brigade, which had fought in the Salamaua-Lae campaign, but in December it was decided to ship it directly to Finschhafen.

The brigade suffered its first casualties on the night of 21/22 January in a friendly fire incident, which was a common occurrence with units inexperienced in jungle warfare.

[37] On 22 January a native reported seeing seven Japanese in the hills south-west of Sio and a patrol was sent out under Corporal Bengari to investigate.

It seems that only about 4,300 of the 7,000 troops under the command of the Japanese 20th Division who had originally been forward of Sio survived the withdrawal, and many of them were rendered ineffective through wounds, sickness, malnutrition and exhaustion.

On the other hand, the new base at Finschhafen was no longer threatened by the Japanese and became an important staging point for the Western New Guinea campaign.

The capture of the Japanese ciphers at Sio allowed General MacArthur to carry out Operations Reckless and Persecution with a plan based upon sound intelligence rather than just his own intuition.