Battle of Hollandia

The Battle of Hollandia (code-named Operation Reckless) was an engagement between American and Japanese forces during World war II. It took place in spring of 1944 and was part of the New Guinea campaign. The landings were undertaken simultaneously with the amphibious landings at Aitape ("Operation Persecution") to the east. The battle was an unqualified success for the US forces, resulting in a withdrawal by the Japanese to a new strategic defence line in the west of New Guinea and the abandonment of all positions in the east of the island.

Background
Hollandia was a port on the north coast of New Guinea, part of the Dutch East Indies, and was the only anchorage between Wewak to the east, and Geelvink Bay to the west. It was occupied by the invading Japanese during the invasion of the Dutch East Indies in 1942 and became a base for their expansion to the east towards the Australian mandated territories of Papua New Guinea.

Hollandia was situated on the east side of a headland separating Humboldt Bay to the east and Tanahmerah Bay, 25 miles to the west. The town itself was on the shore of Humboldt Bay, with a first-class anchorage. The headland was formed by the Cyclops Mountains, a mountain ridge rising steeply to 7,000 ft and was backed by a Lake Sentani, extending 15 miles east to west. Between the mountain ridge and the lake was a narrow plain, where the Japanese had built a number of airfields; three had been completed by April 1944 and a fourth was under construction.

In the spring of 1944 the Allied South West Pacific Command determined that the area should be seized and developed into a staging post for their advance along the north coast of New Guinea into the Dutch East Indies and to the Philippines.

Forces involved
The port and airfields were the base for units of the Japanese 2nd Area Army and the 6th Air Division of the 4th Air Army. These totalled 14,000 men under the command of Maj.Gen. Kitazano and Rear Adm. Endo.

To overcome this force the US 6th Army committed its 1st Corps under Lt.Gen. RL Eichelberger, some 50,000 men and a naval task force of 200 vessels of 7th Fleet under Rear Adm. DE Barbey. The main landings would be at Tanahmera Bay comprising two Regimental Combat Teams (RCT's) of the US 24th Division, and at Humboldt Bay by two RCT’s of 41st Div. These would be supported by two cruiser forces, HMAS Australia & Shropshire under Rear Adm. VAC Crutchley and US cruisers Phoenix, Nashville and Boise under Rear Adm. RS Berkey, supported by a force of eight escort carriers of 5th Fleet.

Action
Initial operations commenced in the second week of March 1944 with air raids by the Fast Carrier Force on Palau and islands in the Carolines, while aircraft of the US 5th Air Force and the RAAF attacked Japanese airfields along the New Guinea coast from Wewak to the Vogelkop and on Biak Island.

On 30 March and continuing to 3 April these air forces attacked Hollandia itself and the airfields on the Sentani plain. Achieving complete surprise they were able to destroy nearly 100 aircraft on the ground, leaving 6 Air Div unable to resist the planned invasion.

On 16 to 18 April the amphibious forces sailed from their bases at Finschafen and Goodenough Island, taking evasive routes to confuse their intentions until they arrived off Hollandia during the night of 21/22 April. The landings took place at dawn on 22 April after a supporting naval bombardment at each site. At Tanahmera Bay the two RCT’s from 24 Div. were able to land without opposition, but found the beach to be highly unsuitable. Backed by a swamp just 30 yards from the shoreline, and with just one exit trail unsuitable for vehicles, Tanahmera Bay was quickly written off as a landing site; while the infantry already ashore pressed on to the Sentani plain the remainder of 24 Div was diverted to Humboldt Bay, which had by this time been secured. After four days under these conditions the two units had reached the western airfield and on 26 April it was secured.

Meanwhile at Humboldt Bay 41 Div. also achieved complete surprise, and though the beaches were defended after the naval bombardment the Japanese troops there uncharacteristically abandoned their positions and fled inland. There was some opposition as they pressed forward, but by 24 April they had reached the lake and by 26 April secured the two eastern airfields. The two forces linked up the same day.

The collapse of Japanese resistance has been attributed to lack of preparedness, due to changes in the command structure and to a lack of combat troops; many of the 11,000 men based there were administrative and support units. None of the senior officers present had been in post more than a few weeks and the senior air officer had been relieved following the destruction of his air forces at the beginning of April. Neither Kitazono nor Endo had been able to prepare a comprehensive defence plan, and in any event had neither the men nor the resources to carry it out. On the other hand the Allied operation had been over-insured; concerns over the strength of the Japanese garrison had left the Allies with a four to one advantage in the event.

Aftermath
Operation Reckless was an unqualified success, and the loss of Hollandia made the Japanese strategic defence line at Wakde, to the west, and all Japanese positions to the east untenable. Japanese forces to the west were reconfigured to form a defence line through Biak and Manokwari, while Japanese 18th Army, still in defensive positions around Wewak, to the east, were faced with a 400 mile retreat through the jungle.

Meanwhile the Allies quickly made the Sentani airfields operational and were able to mount bombing raids on Japanese positions as far west as Biak, making them useless for air operations. The landings at Hollandia and Aitape were followed just four weeks later by landings at Wakde, Sarmi and Toem, to the west.