Operation Mo

Operation Mo (MO作戦 Mo Sakusen) or the Port Moresby Operation was a Japanese plan to take control of the Australian Territory of New Guinea during World War II as well as other locations in the South Pacific with the goal of isolating Australia and New Zealand from their ally the United States. The plan was developed by the Imperial Japanese Navy and supported by Admiral Isoroku Yamamoto, the commander-in-chief of the Combined Fleet. The operation was ultimately abandoned.

Operation Mo
Map showing the movements of the Port Moresby invasion force, and the plan for the force's landing at Port Moresby
Map showing the movements of the Port Moresby invasion force, and the plan for the force's landing at Port Moresby
PlannedApril 1942
ObjectiveOccupation of Port Moresby
OutcomeAbandoned following the Battle of the Coral Sea

Background

When the Japanese Navy was planning the New Guinea Campaign (air strikes against Lae and Salamaua, disembarkation in Huon Gulf, New Britain (Rabaul), New Ireland (Kavieng), Finch Harbor (also called Finschhafen), and the capture of Morobe and Buna), strategists envisioned those territories as support points to implement the capture of Port Moresby. The implementation of these operations was assigned to the Japanese Naval task force led by Admiral Chūichi Nagumo, after completing the Java campaign. Another important step was the occupation of Christmas Island to the south of Java. The Japanese Navy General Staff had been considering Operation Mo since 1938, as a step in the consolidation of the Southern Seas areas in the Greater East Asia Co-Prosperity Sphere (大東亜共栄圏 Dai-tō-a Kyōeiken).

Strategy

The Directive of Operation Mo was conceived in 1938, but with no specific time for its execution, pending earlier successes in the southern area during the first and second phases of the conquest.

In April 1942, the operation was organized into four large actions and was approved by the Army and Navy General Staffs:

  • On 3 May, the Light Task Force occupied the port of Tulagi, near Guadalcanal in the Solomon Islands, to establish a seaplane base and a base for operations in the Coral Sea area. The same force was to take Nauru and Banaba Island (Ocean Island) for their valuable phosphate deposits.
  • The South Seas Detachment was to disembark in Port Moresby on 7 May, with another force occupying territory in the Louisiade Archipelago for another seaplane base.
  • Another objective of the South Sea Detachment was Operation FS, the assault on New Caledonia, Fiji, and Samoa. IGHQ assigned a new double objective: capture and secure Port Moresby, in cooperation with the Navy; and seize strategic points of opportunity in eastern New Guinea.
  • Another important Naval force, departing from Truk, was to pass the Eastern Solomons area to the south, finally advancing toward the west in order to intercept the enemy. Following this, strikes were planned on the coastal cities of Coen, Cooktown and Townsville in Queensland, which were terminal points in the supply line between the United States and Australia. The final object was Thursday Island to the north of Cape York.
  • The Japanese had one Air Naval land-based fleet detached in Rabaul, Lae, Salamaua and Buna. This Air fleet executed the air strikes against Port Moresby on 5 May and 6 May, in preparation for the Japanese landing on 7 May.

Japanese planners took into account an Allied response to the operation by detaching one task force to the west of parallel between of Rennel and Deboyne Islands and another to the east of same point. These measures would permit a Japanese invasion force to use the Jomard Passage directly to Port Moresby. Japanese naval intelligence also suspected the presence of the American aircraft carrier USS Yorktown in Coral Sea waters during this period.

Order of battle

The Tulagi assault force, led by Rear Admiral Kiyohide Shima, was composed of the following units:

The Port Moresby occupation force, led by Rear Admiral Sadamichi Kajioka, was composed of the following units:

Supporting these operations and intercepting any Allied interference, Rear Admiral Aritomo Goto commanded:

During the course of operation, Yamamoto sent the following heavy support force from Truk, led by Rear Admiral Chuichi Hara:

Supporting this force was the 25th Air Fleet, (Yokohama Air Corps) led by Rear Admiral Sadayoshi Yamada, based in Rabaul, Lae, Salamaua, Buna and Deboyne Islands, composed of 60 Mitsubishi A6M "Zero" fighters, 48 Mitsubishi G3M "Nell" and 26 Aichi E13A "Jake" and Mitsubishi F1M "Pete" reconnaissance seaplanes. This unit bombed Port Moresby on 5–6 May, ahead of the Japanese Army-Navy landing on 7 May.

Execution

The Tulagi assault force began their landings on Tulagi on 3 May. On 4 May 1942, troopships bearing the South Seas Detachment set sail southward from Rabaul for Port Moresby. This same day US aircraft from Yorktown attacked the Tulagi assault force, inflicting heavy damage, but were unsuccessful in preventing the occupation of Tulagi, Gavutu, and Tanambogo islands.

Three days later, as a naval engagement appeared to be brewing in the Coral Sea, the Japanese Moresby transports immediately veered back to the north, in order to avoid combat. The resulting Battle of the Coral Sea inflicted significant aircraft losses on the Fourth Fleet, Shōhō was sunk, and Shōkaku was damaged. Air groups from the two carriers, including the relatively undamaged Zuikaku, suffered such sizable losses, it was necessary they return to Japan to re-equip and train.

The Japanese abandoned their plans to land the South Seas Detachment directly at Port Moresby from the sea. The Japanese Army was making new preparations for combat when, on 11 July, High Command ordered the suspension of Operation FS the projected actions against New Caledonia, Fiji, and Samoa, after the remaining Japanese carrier strength was destroyed at the Midway.

These battles prevented the Japanese landings against Port Moresby. Instead the Japanese army commenced an ultimately unsuccessful campaign to take Port Moresby with an overland approach across the Owen Stanley Range via the Kokoda Track.

References

  • Bullard, Steven (translator) (2007). Japanese army operations in the South Pacific Area New Britain and Papua campaigns, 1942–43. Canberra: Australian War Memorial. ISBN 978-0-9751904-8-7.
  • Japanese Demobilization Bureaux (1966). Japanese Operations in the Southwest Pacific Area. Volume II Part I. Reports of General MacArthur. United States Army.
  • Morison, Samuel Eliot (2001) [1949]. Coral Sea, Midway and Submarine Actions, May 1942-August 1942, vol. 4 of History of United States Naval Operations in World War II. Champaign, Illinois, US: University of Illinois Press. ISBN 0-252-06995-1.
  • Rottman, Gordon (2005). Japanese Army in World War II. Conquest of the Pacific 1941–42. Battle Orders. Duncan Anderson (consultant editor). Oxford: Osprey. ISBN 1-84176-789-1.
Alexandria University

Alexandria University (Arabic: جامعة الإسكندرية‎) is a public university in Alexandria, Egypt. It was established in 1938 as a satellite of Fouad University (the name of which was later changed to Cairo University), becoming an independent entity in 1942. It was known as Farouk University until the Egyptian Revolution of 1952 when its name was changed to the University of Alexandria. Taha Hussein was the founding rector of Alexandria University. It is now the second largest university in Egypt and has many affiliations to various universities for ongoing research.

Battle of the Coral Sea

The Battle of the Coral Sea, fought from 4–8 May 1942, was a major naval battle between the Imperial Japanese Navy (IJN) and naval and air forces from the United States and Australia, taking place in the Pacific Theatre of World War II. The battle is historically significant as the first action in which aircraft carriers engaged each other, as well as the first in which the opposing ships neither sighted nor fired directly upon one another.

In an attempt to strengthen their defensive position in the South Pacific, the Japanese decided to invade and occupy Port Moresby (in New Guinea) and Tulagi (in the southeastern Solomon Islands). The plan to accomplish this was called Operation Mo, and involved several major units of Japan's Combined Fleet. These included two fleet carriers and a light carrier to provide air cover for the invasion forces. It was under the overall command of Japanese Admiral Shigeyoshi Inoue.

The U.S. learned of the Japanese plan through signals intelligence, and sent two United States Navy carrier task forces and a joint Australian-U.S. cruiser force to oppose the offensive. These were under the overall command of U.S. Admiral Frank J. Fletcher.

On 3–4 May, Japanese forces successfully invaded and occupied Tulagi, although several of their supporting warships were sunk or damaged in surprise attacks by aircraft from the U.S. fleet carrier Yorktown. Now aware of the presence of U.S. carriers in the area, the Japanese fleet carriers advanced towards the Coral Sea with the intention of locating and destroying the Allied naval forces. On the evening of 6 May, the direction chosen for air searches by the opposing commanders brought the two carrier forces to within 70 nmi (81 mi; 130 km) of each other, unbeknownst to both sides. Beginning on 7 May, the carrier forces from the two sides engaged in airstrikes over two consecutive days. On the first day, both forces mistakenly believed they were attacking their opponent's fleet carriers, but were actually attacking other units, with the U.S. sinking the Japanese light carrier Shōhō while the Japanese sank a U.S. destroyer and heavily damaged a fleet oiler (which was later scuttled). The next day, the fleet carriers found and engaged each other, with the Japanese fleet carrier Shōkaku heavily damaged, the U.S. fleet carrier Lexington critically damaged (and later scuttled), and Yorktown damaged. With both sides having suffered heavy losses in aircraft and carriers damaged or sunk, the two forces disengaged and retired from the battle area. Because of the loss of carrier air cover, Inoue recalled the Port Moresby invasion fleet, intending to try again later.

Although a tactical victory for the Japanese in terms of ships sunk, the battle would prove to be a strategic victory for the Allies for several reasons. The battle marked the first time since the start of the war that a major Japanese advance had been checked by the Allies. More importantly, the Japanese fleet carriers Shōkaku and Zuikaku—the former damaged and the latter with a depleted aircraft complement—were unable to participate in the Battle of Midway the following month, while Yorktown did participate, ensuring a rough parity in aircraft between the two adversaries and contributing significantly to the U.S. victory in that battle. The severe losses in carriers at Midway prevented the Japanese from reattempting to invade Port Moresby from the ocean and helped prompt their ill-fated land offensive over the Kokoda Track. Two months later, the Allies took advantage of Japan's resulting strategic vulnerability in the South Pacific and launched the Guadalcanal Campaign; this, along with the New Guinea Campaign, eventually broke Japanese defenses in the South Pacific and was a significant contributing factor to Japan's ultimate surrender in World War II.

Invasion of Tulagi (May 1942)

The invasion of Tulagi, on 3–4 May 1942, was part of Operation Mo, the Empire of Japan's strategy in the South Pacific and South West Pacific Area in 1942. The plan called for Imperial Japanese Navy troops to capture Tulagi and nearby islands in the British Solomon Islands Protectorate. The occupation of Tulagi by the Japanese was intended to cover the flank of and provide reconnaissance support for Japanese forces that were advancing on Port Moresby in New Guinea, provide greater defensive depth for the major Japanese base at Rabaul, and serve as a base for Japanese forces to threaten and interdict the supply and communication routes between the United States and Australia and New Zealand.

Without the means to effectively resist the Japanese offensive in the Solomons, the British Resident Commissioner of the Solomon Islands protectorate and the few Australian troops assigned to defend Tulagi evacuated the island just before the Japanese forces arrived on 3 May. The next day, however, a U.S. aircraft carrier task force en route to resist the Japanese forces advancing on Port Moresby (later taking part in the Battle of the Coral Sea) struck the Japanese Tulagi landing force in an air attack, destroying or damaging several of the Japanese ships and aircraft involved in the landing operation. Nevertheless, the Japanese troops successfully occupied Tulagi and began the construction of a small naval base.

Over the next several months, the Japanese established a naval refueling, communications, and seaplane reconnaissance base on Tulagi and the nearby islets of Gavutu and Tanambogo, and in July 1942 began to build a large airfield on nearby Guadalcanal. The Japanese activities on Tulagi and Guadalcanal were observed by Allied reconnaissance aircraft, as well as by Australian coastwatcher personnel stationed in the area. Because these activities threatened the Allied supply and communication lines in the South Pacific, Allied forces counter-attacked with landings of their own on Guadalcanal and Tulagi on 7 August 1942, initiating the critical Guadalcanal campaign and a series of combined arms battles between Allied and Japanese forces that, along with the New Guinea campaign, decided the course of the war in the South Pacific.

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Jack Michael is a researcher, professor and author in the field of the experimental analysis of behavior best known for his elucidations of the motivating operation (MO), comprising establishing operation (EO) and abolishing operations (AO).

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Shōhō (Japanese: 祥鳳, "Auspicious Phoenix" or "Happy Phoenix") was a light aircraft carrier of the Imperial Japanese Navy. Originally built as the submarine support ship Tsurugizaki in the late 1930s, she was converted before the Pacific War into an aircraft carrier and renamed. Completed in early 1942, the ship supported the invasion forces in Operation MO, the invasion of Port Moresby, New Guinea, and was sunk by American carrier aircraft on her first combat operation during the Battle of the Coral Sea on 7 May. Shōhō was the first Japanese aircraft carrier to be sunk during World War II.

Japanese minelayer Tsugaru

Tsugaru (津軽) was a large minelayer of the Imperial Japanese Navy that was in service during the early stages of World War II. She was named after the earlier Japanese cruiser Tsugaru, which in turn was named after Tsugaru Peninsula in northwest Aomori Prefecture of Japan. She was commissioned immediately before the start of World War II, and sunk by a US submarine in June 1944.

Japanese submarine I-29

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Kantai Collection (TV series)

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Message Abstraction Layer

The Spacecraft Monitoring & Control (SM&C) Working Group of the Consultative Committee for Space Data Systems (CCSDS), which sees the active participation of 10 space agencies and of the Space Domain Task Force of the Object Management Group (OMG), is defining a service-oriented architecture consisting of a set of standard end-to-end services between functions resident on board a spacecraft or based on the ground, that are responsible for mission operations.

The CCSDS Message Abstraction Layer (MAL) provides message abstraction and generic service patterns to the Mission Operation (MO) services defined in the CCSDS Mission Operations Services Concept.

Motivating operation

Motivating operation (MO) is a behavioristic concept introduced by Jack Michael in 1982. It is used to explain variations in the effects in the consequences of behavior. Most importantly, a MO affects how strongly the person is reinforced or punished by the consequences of their behavior. For example, food deprivation is a motivating operation; if a person is hungry, food is strongly reinforcing, but if a person is satiated, food is less reinforcing. In 2003 Laraway suggested subdividing MOs into those that increase the reinforcing or punishing effects of a stimulus, which are termed establishing operations, and MOs that decrease the reinforcing or punishing effects of a stimulus, which are termed abolishing operations.

Operation Cornflakes

Operation Cornflakes (1944–1945) was a World War II Office of Strategic Services (OSS) Morale Operation (MO). Operation Cornflakes involved tricking the German postal service, Deutsche Reichspost, into inadvertently delivering anti-Nazi propaganda to German citizens through mail.The operation involved special planes that were instructed to airdrop bags of false, but properly addressed, mail in the vicinity of bombed mail trains. When recovering the mail during clean-up of the wreck, the postal service would hopefully confuse the false mail for the real thing and deliver it to the various addresses.

Operation RY

Operation RY was the Imperial Japanese plan to invade and occupy Nauru and Ocean islands in the south Pacific during the Pacific conflict of World War II. The operation was originally set to be executed in May 1942 immediately following Operation MO and before Operation MI, which resulted in the Battle of Midway. The primary reason for the operation was to exploit the islands' supplies of phosphate. After a postponement due to interference by enemy forces, the operation was completed in August 1942.

Raids on Deboyne (1942)

A series of raids on Deboyne were conducted by Allied forces against the Imperial Japanese Navy seaplane base in the Deboyne Islands of the Louisiade Archipelago between 9–11 May 1942. The seaplane base had been set up prior to the Battle of Coral Sea and became untenable and was abandoned by the Japanese, due to proximity to Allied airfields at Port Moresby and the failure of Mo Sakusen (Operation Mo).

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Sadayoshi Yamada (山田 定義, Yamada Sadayoshi, 26 November 1892 – 16 November 1971) was a Vice Admiral in the Imperial Japanese Navy during World War II.

Takatsugu Jōjima

Takatsugu Jōjima (城島 高次, Jōjima Takatsugu, 20 June 1890 – 9 October 1967) was an admiral in the Imperial Japanese Navy during World War II.

USS Lexington (CV-2)

USS Lexington (CV-2), nicknamed "Lady Lex", was an early aircraft carrier built for the United States Navy. She was the lead ship of the Lexington class; her only sister ship, Saratoga, was commissioned a month earlier. Originally designed as a battlecruiser, she was converted into one of the Navy's first aircraft carriers during construction to comply with the terms of the Washington Naval Treaty of 1922, which essentially terminated all new battleship and battlecruiser construction. The ship entered service in 1928 and was assigned to the Pacific Fleet for her entire career. Lexington and Saratoga were used to develop and refine carrier tactics in a series of annual exercises before World War II. On more than one occasion these included successfully staged surprise attacks on Pearl Harbor, Hawaii. The ship's turbo-electric propulsion system allowed her to supplement the electrical supply of Tacoma, Washington, during a drought in late 1929 to early 1930. She also delivered medical personnel and relief supplies to Managua, Nicaragua, after an earthquake in 1931.

Lexington was at sea when the Pacific War began on 7 December 1941, ferrying fighter aircraft to Midway Island. Her mission was cancelled and she returned to Pearl Harbor a week later. After a few days, she was sent to create a diversion from the force en route to relieve the besieged Wake Island garrison by attacking Japanese installations in the Marshall Islands. The island surrendered before the relief force got close enough, and the mission was cancelled. A planned attack on Wake Island in January 1942 had to be cancelled when a submarine sank the oiler required to supply the fuel for the return trip. Lexington was sent to the Coral Sea the following month to block any Japanese advances into the area. The ship was spotted by Japanese search aircraft while approaching Rabaul, New Britain, but her aircraft shot down most of the Japanese bombers that attacked her. Together with the carrier Yorktown, she successfully attacked Japanese shipping off the east coast of New Guinea in early March.

Lexington was quickly refitted in Pearl Harbor at the end of the month and rendezvoused with Yorktown in the Coral Sea in early May. A few days later the Japanese began Operation Mo, the invasion of Port Moresby, Papua New Guinea, and the two American carriers attempted to stop the invasion forces. They sank the light aircraft carrier Shōhō on 7 May during the Battle of the Coral Sea, but did not encounter the main Japanese force of the carriers Shōkaku and Zuikaku until the next day. Aircraft from Lexington and Yorktown badly damaged Shōkaku, but the Japanese aircraft crippled Lexington. A mixture of air and aviation gasoline in her improperly drained aircraft fueling trunk lines (which ran from the keel tanks to her hangar deck) ignited, causing a series of explosions and fires that could not be controlled. Lexington was scuttled by an American destroyer during the evening of 8 May to prevent her capture. The wreck of Lexington was located in March 2018 by an expedition led by Paul Allen, who discovered the ship about 430 nautical miles (800 km) off the northeastern coast of Australia in the Coral Sea.

Zuihō-class aircraft carrier

The Zuihō class (瑞鳳型) was a group of two aircraft carriers built for the Imperial Japanese Navy before World War II. Both ships were originally built as submarine tenders, but were subsequently converted into carriers. Completed in early 1942, Shōhō supported the invasion forces in Operation MO, the invasion of Port Moresby, New Guinea, and was sunk by American carrier aircraft on her first combat operation during the Battle of the Coral Sea on 7 May. Shōhō was the first Japanese aircraft carrier to be sunk during World War II. Zuihō played a secondary role in the Battle of Midway in mid-1942 and did not engage any American aircraft or ships during the battle. The ship participated in the Guadalcanal Campaign during the rest of 1942. She was lightly damaged during the Battle of the Santa Cruz Islands during this campaign and covered the evacuation of Japanese forces from the island in early 1943 after repairs.

Afterwards, her aircraft were disembarked several times in mid to late 1943 and used from land bases in a number of battles in the South West Pacific. Zuihō participated in the Philippine Sea and Leyte Gulf in mid-1944. In this last battle, Zuihō mainly served as a decoy for the main striking forces and she was finally sunk by American aircraft fulfilling her task. In between engagements, the ship served as a ferry carrier and a training ship.

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