The battle of Kankiryo Saddle (20 January-1 February 1944) saw Australian troops finally force the Japanese to abandon a key position in the Finisterre Mountains of New Guinea, after a period of difficult fighting on jungle-clad mountain ridges that had begun in October 1943 with the first clashes on the famous Shaggy Ridge.
The Kankiryo Saddle was the watershed between two valleys, the Faria Valley, which runs south towards the main Ramu Valley and the Mindjim River, which flows north-west then north, eventually flowing into Astrolabe Bay on the north coast of New Guinea. It was thus a key position for the Japanese, who were attempting to shield the 20th and 51st Divisions as they retreated along the north coast towards Madang from the Huon Peninsula. At the start of 1944 the area was defended by just under 800 men from the II/78th Battalion, commanded by Captain Yano.
On 2 January the Americans landed at Saidor, behind the Japanese position on the north coast. This triggered a decision to abandon Sio and nearby bases, bypass Saidor, and concentrate at Madang. With the key position on Shaggy Ridge already lost, the Japanese thus needed to hold the Kankiryo Saddle until the 20th and 51st Divisions had passed the danger zone.
The attack was to be carried out by Brigadier Chilton's 18th Brigade, which had been flown into the area at the start of January. The 2/9th Battalion was posted on Shaggy Ridge, with the 2/10th on its right in the Faria valley and the 2/12th in reserve.
As always on New Guinea the difficult terrain decided the lines of attack. The Faria River flows south-east from Kankiryo, with Shaggy Ridge to the west and a ridge running from Crater Hill to Cam's Hill to the east. This ridge ended at the valley of Mainstream, a tributary of the Faria that flows west, running into it near Irie. Two ridges ran north from Mainstream - one heading from the Irie area towards Cam's Hill, and another, Sprogg's Ridge, running north from a position further east. This reached Cam's Saddle, a lower ridge that ran up to Cam's Hill. One other line of approach was up the Mene River, which flows down the valley west of Shaggy Ridge, to Canning's Saddle, then up the southern slopes of Mount Prothero 1, to the west of the Kankiryo Saddle.
Brigadier Chilton decided to make his main assault from Canning's Saddle and Prothero 1. Patrols had found a ridge that led up onto Prothero, although the summit appeared to be held by the Japanese. The 2/12th would carry out the main assault. The 2/10th would carry out a diversionary attack from Cam's Saddle. Once Prothero 1 had been captured the 2/10th would advance both ways along Faria Ridge, north towards Kankiryo and south towards Mainstream. In the middle the 2/9th would attack along Shaggy Ridge, mainly to distract the Japanese.
A five stage plan was set out. Phase one was the advance to Cam's Saddle, set for the 19th. Phase two was the capture of Cam's Saddle, the main action for the 20th. Phase three was the main assault on Prothero 1 from the south-west on the 21st. Phase Four was the attack along Shaggy Ridge, to join up with the 2/12th. Phase Five was the capture of the high ground north of Kankiryo Saddle. The last two phases would begin once the first three were over.
D-Day for the attack (Operation Cutthroat) was set for 20 January. Preliminary operations on 19 January saw the 2/12th reach Geyton's Hill, where the Mene River turns west away from Shaggy Ridge, while the 2/10th advanced up Sprogg's Ridge and reached the eastern end of Cam's Saddle.
The main attack began at 8.45am when the 2/10th began its attack along Cam's Saddle. At 9.30 a force of B-25 Mitchells bombed Prothero and Kankiryo Saddle, while some Vultee Vengeances hit Shaggy Ridge and Prothero. By the end of the day the 2/10th had almost reached the western end of the saddle, but they were held up by a strong Japanese position.
On the other flank the 2/12th reached Canning's Saddle by 3.30pm and rested in the order they expected to attack in on the following day.
The 2/12th began to move at 8.30am on the morning of 21 January. The terrain was so steep that it needed to use ladders to reach its starting point, and it wasn't in place until 9.20am. The plan was for a silent approach, and the leading units got to within 100 yards of the summit before being discovered. They were able to take the top of Prothero 1 at 1.20pm, and prepared to move south-east towards Prothero 2. They had to abandon this plan when they came under very short range fire from a Japanese 75mm gun at 3pm. The first attack on the gun began at 4pm, and it finally fell at 5.30pm. The 2/12th then dug in for the night on Prothero 1.
Further south the 2/9th began its offensive along Shaggy Ridge. Its first target was a Japanese strongpoint at Green Sniper's Pimple, the southern end of McCaughey's Knoll, the highest point on the ridge. The attack began at 10.30am, and Green Sniper's Pimple was taken by 2pm. The Japanese launched a series of counterattacks, but were unable to shift the Australians. Although the 2/9th had only advanced 100 yards during the day, it had captured a key position.
To the east the 2/10th made some progress north along Faria Ridge, and dug in about one mile to the south of the main defences of Kankiryo Ridge.
22 January was the key day on Shaggy Ridge. At 8.30am the 2/12th advanced south-east towards Prothero 2. They reached the saddle between the two peaks by 9.30am, and captured the ridge after a daring attack by Private Bugg, a Bren gunner. From about noon the 2/12th advanced south along Shaggy Ridge, until at 3.30pm they were stopped by Japanese machine gun position. By this point they could see the 2/9th further south along the ridge, and were ordered to prepare for an attack on the following day.
To the south the 2/9th attempted to find a way to attack McCaughey's Knoll from the south west. The advance began at 6pm, but the Australians weren’t spotted until 6.25. Despite heavy Japanese fire they managed to clear McCaughey's Knoll and by the end of the day the 2/9th and 2/12th were only 900 yards apart.
In the east the 2/10th got to the point where Cam's Saddle reached Faria Ridge. They then pushed north, taking Cam's Hill by 5.20pm, and south down the ridge towards Mainstream. They were held up by Japanese defences towards the base of the southern ridge and had to withdraw without achieving success.
Overnight and early on 23 January the 2/12th repulsed two Japanese counter-attacks. The 2/12th and 2/9th then advanced towards each other along Shaggy Ridge, and by just after noon the two units had joined up. Shaggy Ridge was finally in Australian hands.
Another company from the 2/12th headed east down Prothero 2 and captured Kankiryo Saddle. They then ran into a strong Japanese position on Crater Hill, and withdrew to the saddle for the night.
On Faria Ridge the 2/10th discovered that the Japanese had evacuated their positions on Mainstream. In the north the 2/10th made progress along the ridge, and ended the day about half way along the ridge.
By the start of 24 January the Japanese had withdrawn from Faria Ridge. Their main position in the area was now on Crater Hill, their former regimental HQ, 800 yards north of Kankiryo.
The 25th saw the 2/10th and 2/12th probe the Japanese defences on Crater Hill, while the 2/12th send a patrol north-west from Kankiryo. Brigadier Chilton decided to avoid a frontal assault by sending the 2/9th on a wide outflanking movement.
By 5pm the 2/9th was in place behind the Japanese position on Crater Hill, and the Japanese were surrounded. Chilton decided that it wasn't worth the risk of a frontal assault on this last Japanese position, and so instead prepared for more of a siege.
On 27-28th the Australians surrounded Crater Hill and conducted an artillery bombardment, firing 2,000 shells into the Japanese positions.
During the afternoon of 29th January the 2/9th attempted an attack up the western slopes of Crater Hill, but they were repulsed by strong Japanese defences.
30th January was quiet, but on the 31st it became clear that the Japanese had abandoned some of their positions. The 2/9th was able to advance some way on their front and got to within 100 yards of the summit of the hill.
The main part of the battle finally ended on 1 February when parts of the 2/9th and 2/10th reached the top of Crater Hill, finding that the Japanese had escaped in the night, leaving behind them a number of dead, quite a few weapons, and a strong defensive position.
This ended the serious fighting in the Shaggy Ridge and Kankiryo areas. The Australians moved into new positions around the saddle and surrounding hills, with the expectation that they would be in place for some time. Some patrols were sent down the Mindjim valley, where they skirmished with small parties of Japanese troops. Their orders were to stay in place, and not to advance to the coast, but over the next couple of months their commanders managed to interpret their orders to allow an increasing effort to be made in the north. This ended in success when the first troops reached Bogadjim on the coast on 13 April. By then the Japanese had decided to abandon Madang, which had now been isolated by Allied landings on New Britain and in the Admiralty Islands. The Australians made an unopposed entry in Madang on 24 April, effectively ending the whole Markham-Huon campaign and with it the New Guinea part of Operation Cartwheel.