Operation MO

The map shows the movements of the invasion fleet for Port Moresby and their plan for landing

date	April 1942 (planning) - May 3, 1942 (execution)
place	Port Moresby , New Guinea (not reached), Tulagi , Solomon Islands
output	Operation aborted due to the outcome of the Battle of the Coral Sea
consequences	Operation was not resumed by the Japanese, but attempted land routes to capture the city.

Parties to the conflict
United States 48 United States Australia Australia	Japanese Empire Japan

Overview - Pacific War

The operation Mo (Mo Sakusen) or Port-Moresby-operation was the name given to the Japanese plan, during the Second World War in May 1942, the supply routes to Southeast Asia via Australia and New Zealand from the United States cut off. To this end, control of the Australian territory of New Guinea and other islands in the South Pacific should be won. The operation failed, partly due to the battle in the Coral Sea .

Operation planning

As early as 1938, the General Staff of the Japanese Navy had planned the capture of Port Moresby as an important step in the planning for the development of the Greater East Asian sphere of prosperity . In the further planning for the conquest of New Guinea, which included the capture of Lae and Salamaua , the landing in the Huongolf , in Rabaul in New Britain , Kavieng in New Ireland , Finschhafen , Morobe and Buna , these places were named as important supply and support points, to reach and capture Port Moresby. To conclude the operation, surprise attacks were planned on Nauru and Ocean Island in order to be able to exploit the phosphorus deposits on the islands.

Furthermore, the establishment of a Japanese base in Tulagi on the southern Solomon Islands was planned. This should previously Shortland Iceland are taken as an interim basis, this had been carried out until the end of March 1942nd

The execution of the sea operation was incumbent on Admiral Shigeyoshi Inoue after the operations on Java were completed and the further important step, the capture of Christmas Island south of Java (→ Conquest of Christmas Island ).

The Navy also dubbed Operation Mo and set May 3 as the date for the attack on Tulagi and May 10 for the attack on Port Moresby. Nauru and Ocean Island were due to fall on May 15th.

In March 1942, the decision as to whether Port Moresby should be captured by means of a direct or indirect attack by land was still open. Since Allied attacks in the Coral Sea were to be expected, some commanders spoke out in favor of the land action, which, however, had to lead from the north over the Owen Stanley Mountains and was associated with a not inconsiderable effort. A third option would have been extensive night landings within a radius of 110 km west and east of Port Moresby, but this would have required additional approach time to the target of a calculated 5 days. So the decision was made relatively quickly in favor of a direct standard landing operation, which should be covered by appropriate fleet units for shielding.

The preparation

The first reconnaissance flights over Port Moresby were flown from April 10th, which were then replaced by land-based bombers, which flew over the mountains at an altitude of 6,000 m in order to then bomb the city. Education had become ineffective because the results were predictable.

Fighter planes aboard the Zuikaku.

The 4th Fleet asked the High Command for the planned operation to reinforce its naval and air forces. Therefore, she was also assigned the aircraft carrier Kaga , the light aircraft carrier Shōhō , the seaplane tender Zuihō , the 5th cruiser squadron and the 7th and 20th destroyer squadrons. Further negotiations resulted in the exchange of the kaga, which was being repaired in Sasebo in the dry dock , against the two porters Shōkaku and Zuikaku . The land-based combat aircraft and bombers of the 25th Air Fleet on the bases in Rabaul and Lae were available to the 4th Fleet for further air support. They were supposed to neutralize enemy forces in northeast Australia, New Caledonia and the Fiji area, and patrol the south and east of New Guinea, the Bismarck Archipelago and the Coral Sea in order to attack mobile enemy units located there and disrupt their supply lines. Furthermore, a direct cooperation with the landing units was planned as well as the search for the enemy fleet and its destruction. However, since all flight squadrons stationed on these bases had been decimated to a greater or lesser extent during the fighting in Southeast Asia up to April 1942, they were currently largely subject to repairs, restructuring and replacement deliveries, so that none of them were their intended until the start of the operation Achieved strength. Added to this were the intensified Allied air raids on the aforementioned bases.

A SBD Dauntless squadron from Yorktown en route to Lae in March 1942.

The first large-scale air strikes on Port Moresby began on April 17th and were carried out every day from then until early May. In return, the Allies bombed Rabaul and Lae.

The planned units for the assigned invasion fleets gathered in the ports of Rabaul and Truk by the end of April .

Execution

Although the Allies had intercepted and decoded many of the Japanese radio messages relating to Operation Mo, Tulagi was captured on May 3rd without any resistance by the 3rd Kure Special Landing Unit, which had been brought up by Truk. The Australian soldiers stationed there, who were deployed to maintain the four Consolidated PBY seaplanes, had left Tulagi due to the bombing of the aircraft that had taken place the day before. This seemed to pave the way for the Japanese to complete Operation Mo.

But Admiral Chester W. Nimitz had already ordered Task Force 17 (TF17) with the USS Yorktown and Task Force 11 (TF11) with the USS Lexington into the Coral Sea. On May 1, the two fleets united under Vice Admiral Frank Jack Fletcher 500 km northwest of New Caledonia in search of the Japanese invasion fleet. At around 5:00 p.m. on May 3, Fletcher found out about the Tulagi operation. Since he had to maintain radio silence, he could not reach the TF11 and turned the TF17 on course for Guadalcanal . The next morning the USS Yorktown was in position to launch a first air strike on the Japanese in Tulagi. In total, the pilots of the USS Yorktown flew three missions that day, during which they were able to sink a destroyer, two minesweepers and smaller units and damage other ships. The Americans lost three fighter planes that crashed because their tanks were empty.

After the TF11 stopped to refuel, the two task forces reached their search area in the Coral Sea on May 4th.

Damage to the Shōkaku after the battle.

On May 2 and 3, the Japanese ships carrying the landing units for Port Moresby left the port of Rabaul together with their escort fleet. A scheduled refueling stop was made about 670 km north of Tulagi. Meanwhile, the report of the American air raid on Tulagi reached the fleet, so that the presence of one or more US carriers was known to the Japanese. Shortly thereafter, the high command issued the order to search for and destroy the American carrier fleet. The Japanese escort fleet for Operation MO then immediately set course south. After a long search, the Battle of the Coral Sea broke out on May 7th and 8th , in which the Americans lost the USS Lexington and the Japanese lost the Shōhō . The USS Yorktown suffered severe damage, as well as the Shōkaku and almost all of the Zuikaku's fighter aircraft were destroyed.

As a result, adequate coverage of the landing forces for Port Moresby was no longer guaranteed and Operation MO was initially postponed by 2 days by the High Command. The Japanese fleet set north course, but on the morning of 8 May a radio message was sent calling for the complete destruction of the Allied fleet. But after the American ships could not be found by the afternoon, Operation MO was completely suspended and the fleet asked to return to Rabaul.

credentials

↑ Bullard, Steven: Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43, Australian War Memorial, page 54 ff under: [1]
^ IJN Kaga: Tabular Record of Movement, under
↑ Bullard, Steven: Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43, Australian War Memorial, page 51 ff under: [2]
↑ Bullard, Steven: Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43, Australian War Memorial, page 52 under: [3]

Web links

Commons : New Guinea Campaigns - Collection of images, videos and audio files

Why the Japanese were in New Guinea (Symposium paper), by Dr. Henry Frei (Tsukuba Women's University) - (English)
Remembering the war in New Guinea , by Prof. Arakawa Ken'ichi (National Institute of Defense Studies) - (English)

[awm01-1] Bullard, Steven: Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43, Australian War Memorial, page 54 ff under: [1]

[combfl01-2] IJN Kaga: Tabular Record of Movement, under

[awm02-3] Bullard, Steven: Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43, Australian War Memorial, page 51 ff under: [2]

[awm03-4] Bullard, Steven: Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43, Australian War Memorial, page 52 under: [3]