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.
Background
On 7 December 1941, the Japanese attacked the U.S. Pacific Fleet at Naval Station Pearl Harbor, Hawaii. The attack crippled most of the U.S. Pacific Fleet's battleships and started a formal state of war between the two nations. In launching this war, Japanese leaders sought to neutralize the American fleet, seize possessions rich in natural resources, and obtain strategic military bases to defend their far-flung empire. Soon after, other nations—including the United Kingdom, Australia, and New Zealand—joined the U.S. as Allies in the war against Japan. In the words of the Japanese Navy's Combined Fleet "Secret Order Number One", dated 1 November 1941, the goals of the initial Japanese campaigns in the impending war were to, "(eject) British and American strength from the Netherlands Indies and the Philippines, (and) to establish a policy of autonomous self-sufficiency and economic independence". To support these goals, during the first few months of 1942 Japanese forces also attacked and took control of the Philippines, Thailand, Malaya, Singapore, the Netherlands East Indies, Wake Island, New Britain, the Gilbert Islands, and Guam.
Vice Admiral Shigeyoshi Inoue—commander of the Japanese 4th Fleet (also called the "South Seas Force") consisting of most of the naval units in the South Pacific area—advocated the seizing of Lae, Salamaua, and Port Moresby in New Guinea and Tulagi in the Solomon Islands. Inoue believed that the capture and control of these locations would provide greater security for the major Japanese base at Rabaul on New Britain. Japan's Naval General Staff endorsed Inoue's argument and began planning further operations, using these locations as supporting bases, to seize Nauru, Ocean Island, New Caledonia, Fiji, and Samoa and thereby cut the supply lines between Australia and the U.S., with the goal of reducing or eliminating Australia as a threat to Japanese positions in the South Pacific.
The Imperial Japanese Army supported the idea of taking Port Moresby and in April 1942, with the Japanese Navy, developed a plan for the attack that was titled "Operation Mo". The plan also included the seizure of Tulagi, a small island in the southern Solomon Islands, where a seaplane base would be set up for potential air operations against Allied territories and forces in the South Pacific. Although Japanese Admiral Isoroku Yamamoto—commander of the Combined Fleet—was concurrently planning an operation that he hoped would lure the U.S. Pacific Fleet into a decisive showdown in the central Pacific, he detached some of his large warships to support the Mo operation and placed Inoue in charge of the naval portion of the operation.
A large force consisting of two heavy aircraft carriers, one light aircraft carrier, a seaplane carrier, nine cruisers, and 13 destroyers—split into several elements—was to guard the Japanese Port Moresby invasion convoy as well as to engage any Allied naval warships that approached to contest the invasion. The Tulagi invasion force, consisting of the destroyers Kikuzuki and Yūzuki; minelayer/transports Okinoshima, and Kōei Maru; auxiliary minesweepers Wa-1, Wa-2, Hagoromo Maru, Noshiro Maru #2, and Tama Maru; transport, Azumasan Maru; subchasers Toshi Maru #3 and Tama Maru #8; and commanded by Rear Admiral Kiyohide Shima (flag on Okinoshima), departed from Rabaul on 30 April and headed towards the Solomon Islands. Rear Admiral Aritomo Gotō provided air cover for the Tulagi invasion with his Covering Group of one light carrier (Shōhō), four cruisers, and one destroyer located just west of the central Solomons. A separate Cover Force (sometimes referred to as the Tulagi Support Group)—commanded by Rear Admiral Kuninori Marumo and consisting of two light cruisers, the seaplane tender Kamikawa Maru, and three gunboats—joined the Covering Group in supporting the Tulagi invasion. Once Tulagi was secured on 3 or 4 May, the Covering Group and Cover Force were to reposition to help cover the Port Moresby invasion.
At the time, Tulagi was the capital of the British Solomon Islands Protectorate, which included all of the islands of the Solomons except Bougainville and Buka. William Sydney Marchant, the British Resident Commissioner of the Solomons and commander of the local defense forces, directed the evacuation of most of the white civilian residents to Australia in February 1942. Marchant was evacuated to Malaita the following month, where he helped operate a coastwatcher relay station.
The only Allied military forces at Tulagi were 24 commandos from the Australian Army's 2/1st Independent Company, under Captain A. L. Goode, and about 25 personnel from 11 Squadron RAAF, under F/O R. B. Peagam, operating a seaplane base on nearby Gavutu-Tanambogo with four PBY Catalina maritime patrol aircraft. Three Allied coastwatchers were also located nearby, on Guadalcanal island. The task of the coastwatchers was to report on any enemy movements, or suspicious activity, that they observed in the vicinity of their stations. In the belief that it might prevent them being executed for espionage, all of the coastwatchers were commissioned as Royal Australian Naval Volunteer Reserve officers, and they were directed by Lieutenant Commander Eric Feldt, who was located at Townsville in Australia.
Throughout most of April, the Japanese conducted "desultory" bombing raids on Tulagi with aircraft based at Rabaul or nearby that caused little, if any, damage. The coastwatchers on Guadalcanal were usually able to radio advance warning to the Australian troops on Tulagi of the approaching Japanese aircraft, but the troops did not have large enough weaponry—three Vickers machine guns and one Bren light machine gun—to seriously challenge the Japanese bombers. On 25 April, Tulagi was bombed by eight Japanese aircraft. Similar raids occurred daily over the next week, with one raid on 1 May heavily damaging one of the Catalinas at Gavutu. The remaining Catalinas successfully evacuated that same day.
Allied intelligence personnel had deciphered much of the Japanese Mo plans through radio intercepts at the Allied Fleet Radio Units (radio intelligence centers) in Melbourne, Australia and Pearl Harbor, Hawaii. Based on this intelligence, on 22 April, U.S. Admiral Chester Nimitz—stationed at Pearl Harbor—directed Allied forces towards the Coral Sea area to interdict the Japanese Mo operation. On 27 April, the U.S. aircraft carrier USS Yorktown's Task Force 17 (TF 17), under the command of Rear Admiral Frank Jack Fletcher, sortied from Tonga and was joined by the U.S. carrier USS Lexington's TF 11 300 nmi (350 mi; 560 km) northwest of New Caledonia on 1 May. That same day, Fletcher detached TF 11 to refuel, expecting to rejoin with Lexington and her escorts on 4 May at a predetermined location in the Coral Sea.
Landings and air attacks
On 2 May, coastwatcher Jack Read on Bougainville reported that a large force of Japanese ships, believed to be part of the Japanese Tulagi invasion force, had departed from the Buka area. Later that day, coastwatcher D. G. Kennedy on New Georgia island sighted and reported a large Japanese force of ships heading towards the southern Solomons. Soon after, Goode and Peagam—anticipating that the Japanese would attack with overwhelming numbers—ordered the execution of a pre-planned evacuation operation and began the destruction and demolition of their equipment and facilities on Tulagi and Gavutu-Tanambogo. The RAAF personnel and commandos embarked on two small ships early in the morning on 3 May to begin the trip to Vila, New Hebrides, just as Shima's ships entered Savo sound to begin their landings on Tulagi. The ship with the RAAF personnel spent the day with coastwatcher and protectorate District Officer Martin Clemens at Aola on Guadalcanal and departed that night.
Supporting the Japanese landings were seaplanes from Kamikawa Maru, temporarily based at Thousand Ships Bay at Santa Isabel Island. About 400 Japanese naval troops—mainly from the Kure 3rd Special Naval Landing Force—disembarked from the transport ship on barges and immediately began construction of facilities on Tulagi and Gavutu-Tanambogo. Aircraft from Shōhō covered the landings until early afternoon, when Gotō's force turned toward Bougainville to refuel in preparation to support the landings at Port Moresby. Once the Japanese troops were ashore, six seaplanes landed in Tulagi harbor as part of the establishment of the planned seaplane base there.
At 17:00 on 3 May, Fletcher was notified that the Japanese Tulagi invasion force had been sighted the day before approaching the southern Solomons. Unable to communicate with the Lexington task force because of the need to maintain radio silence, Yorktown's task force proceeded independently toward Guadalcanal in order to be in position to launch airstrikes against the Japanese forces at Tulagi the next morning.
At 07:01 on 4 May, Yorktown launched a first strike consisting of 12 TBD Devastator torpedo bombers and 28 SBD Dauntless dive bombers from a position about 160 km (86 nmi; 99 mi) south of Guadalcanal. The aircraft began their attacks on Shima's ships anchored near Tulagi at 08:50, taking the Japanese ships by surprise and at anchor. Okinoshima and the two destroyers were positioned to provide a protective barrier for Azumasan Maru and Kōei Maru which were busy unloading troops and materiel. The three minesweepers had just got underway to support the Port Moresby invasion and were still near Tulagi. Although the U.S. pilots from the first strike claimed many bomb and torpedo hits on the anchored ships, they actually hit only Okinoshima, causing minor damage, and Kikuzuki, causing major damage. Kikuzuki—with the assistance of one of the subchasers—was beached on Gavutu in an attempt to keep her from sinking. During this time, all of the other ships weighed anchor and attempted to escape from the harbor. One U.S. dive bomber destroyed a Japanese Mitsubishi F1M2 "Pete" floatplane that attempted to take off during the attack.
Yorktown's second strike—utilizing the same aircraft—returned to Tulagi and began their attack at 12:10 on the Japanese ships, many of which were now at full steam and attempting to put distance between themselves and Tulagi harbor. The second strike hit and sank the minesweepers #1 and #2 and severely damaged Tama Maru northeast of Savo Island. Another Japanese seaplane was shot down by a U.S. dive bomber during the second strike. After four F4F-3/3A Wildcat fighters from Yorktown joined the strike, the fighters shot down two more Japanese floatplanes over Florida Island. The four U.S. fighters then strafed Yūzuki, killing her captain and nine others of her crew, and causing moderate damage to the ship. Two or three other Japanese floatplanes were damaged in Tulagi harbor and their crews were killed.
A third, smaller strike from Yorktown arrived at 15:30 and caused moderate damage to Azumasan Maru and Okinoshima. One of the TBDs (Bu No. 0333) in the third strike became lost, ran out of fuel, and ditched in the ocean about 60 km (32 nmi; 37 mi) south of Guadalcanal. Two of the Wildcats from the second strike also ran out of fuel and crash landed on the southern coast of Guadalcanal. Fletcher sent the destroyers USS Hammann and Perkins to rescue the aircrews from the three aircraft. Hammann was able to recover both fighter pilots, but Perkins was unable to locate the TBD's crew. Both destroyers returned to Yorktown's task force late that evening as the task force turned away from Guadalcanal toward the southeast in order to refuel and rendezvous with Lexington the next day.