Japanese cruiser Chikuma (1938)

The Chikuma (筑摩 重巡洋艦) was the second and last vessel in the Tone-class of heavy cruisers in the Imperial Japanese Navy. It is named after the Chikuma River, in Nagano prefecture of Japan. The Tone-class cruisers were originally envisaged as the 5th and 6th vessels in the Mogami class. However, by the time construction began, serious weaknesses in the Mogami-class hull design had become clear following the Fourth Fleet Incident in 1935. As Japan no longer was obligated to abide by the limitations of the London Naval Treaty, a new design was created and new means of construction were utilized. Though the external dimensions were close to the Mogami class, the design was quite different, with all the main battery of guns placed forward of the bridge, reserving the entire stern area as a large sea plane hangar. Unlike the U.S. Navy, the Japanese did not have a dual role attack/scout aircraft. No reconnaissance units were assigned to the Japanese carriers, and little emphasis was placed on this aspect of carrier warfare. Instead the Japanese reserved all of their carrier aircraft for attack roles. Reconnaissance was left up to float planes carried by cruisers. The Chikuma was intended to provide the long range scout planes needed for their carrier Air Fleets.

Background
Chikuma was designed for long-range scouting missions and had a large seaplane capacity. She was extensively employed during the World War II in conjunction with an aircraft carrier task force, or as part of a cruiser squadron with her sister ship, Tone.

Early career
Chikuma was completed at Mitsubishi Nagasaki shipyards on 20 May 1939. After several months as a unit of the Crudiv6 (Sentai 6) of the Second Fleet, she was transferred to the CruDiv8 in November 1939. In addition to taking part in regular combat exercises in Japanese home waters, she operated off southern China on three occasions between March 1940 and March 1941.

Early stages of the Pacific War
At the end of 1941, Chikuma was assigned to CruDiv 8 with its sister ship, Tone, and was thus one of the key players in the attack on Pearl Harbor. On 7 December 1941, Tone and Chikuma each launched one Aichi E13A1 Type 0 "Jake" floatplane for a final weather reconnaissance over Oahu. At 0630, Tone and Chikuma each launched short range Nakajima E8N Type 95 "Dave" two-seat floatplanes to act as pickets and patrol south of the Striking Force. Chikuma's floatplane reported nine anchored battleships (presumably counting Utah as a battleship). During the subsequent attack, the USS Arizona, USS Oklahoma, USS West Virginia and USS California were sunk and USS Nevada, USS Pennsylvania (BB-38), USS Tennessee, USS Maryland and other smaller ships were damaged.

On 16 December, CruDiv 8 was ordered to assist in the second attempted invasion of Wake Island. Anti-aircraft fire damaged the scout plane from Chikuma, which was forced to ditch, but the crew was rescued. After the fall of Wake Island, CruDiv 8 returned to Kure, Hiroshima.

On 14 January 1942, CruDiv 8 was based out of Truk in the Caroline Islands, and covered the landings of Japanese troops at Rabaul, New Britain and attacks on Lae and Salamaua, New Guinea. On 24 January Chikuma's floatplanes attacked the Admiralty Islands.

After the 1 February air raid on Kwajalein by Vice Admiral William Halsey, Jr's USS Enterprise (CV-6), Chikuma departed Truk with the Carrier Striking Force in an unsuccessful pursuit. Chikuma and Tone later participated in the Raid on Port Darwin, Australia on 19 February, sinking 11 ships. From 25 February 1942, Chikuma was involved in supporting the Japanese invasion of Java.

Battle of the Java Sea
On 1 March 1942, Chikuma's floatplane located the 8,806-ton Dutch freighter Modjokerto attempting to escape from Tjilatjap to Australia. Chikuma, with Tone, and destroyers Kasumi and Shiranui intercepted and sank the freighter before noon. That afternoon, CruDiv 8's spotted the old destroyer USS Edsall, 250 miles SSE of Christmas Island. Chikuma opened fire with her 8-inch guns at the extremely long range of 11 miles, and all shots missed. Chikuma was joined by battleships Hiei and Kirishima, which also opened fire with their 14 inch main batteries, but the Edsall not only managed to avoid 297 14-inch, 132 6-inch shells from the battleships and an additional 844 8-inch and 62 5-inch rounds from the cruisers, but it also closed to range and fired its 4-inch guns at Chikuma. Hits from Hiei, Tone and dive bombers from the Sōryū and Akagi finally stopped Edsall, which was then finished off by Chikuma.

On 4 March, Chikuma sank the 5,412-ton Dutch merchant Enggano (which had earlier been damaged by a floatplane from Takao). On 5 March, floatplanes from Tone and Chikuma took part on the strike against Tjilatjap. After the surrender of the Dutch East Indies, Chikuma was assigned to Indian Ocean operations.

Indian Ocean raids
On 5 April 1942, Chikuma was part of a major task force which launched 315 aircraft against Colombo, Ceylon. HMS Tenedos, HMS Hector and 27 aircraft were destroyed and over 500 killed in harbor, and the cruisers HMS Cornwall (56) and HMS Dorsetshire (40) were destroyed at sea. After searching for more remnants of the Royal Navy, the Indian Ocean Task Force launched 91 Aichi D3A1 "Val" dive-bombers and 41 Mitsubishi A6M2 "Zeke" fighters on 9 April against the British naval base at Trincomalee, Ceylon. They found the harbor empty, but wrecked the base's facilities and shot down nine planes, and later sank the carrier HMS Hermes, HMAS Vampire, and corvette HMS Hollyhock, an oiler and a depot ship at sea 65 mi from base.

The task force with Chikuma returned to Japan in mid-April 1942, where it was almost immediately assigned to the unsuccessful pursuit of Admiral Halsey's Task Force 16.2 with the USS Hornet after the Doolittle Raid.

Battle of Midway
At the crucial Battle of Midway, Chikuma and CruDiv 8 was in Vice Admiral Chuichi Nagumo's Carrier Striking Force. On 4 June, Tone and Chikuma each launched two Aichi E13A1 "Jake" long-range reconnaissance floatplanes to search out 300 mi for American carriers. The Tone floatplane discovered American ships, but did not recognize that the fleet was a carrier group, which proved to be a crucial mistake. Chikuma's floatplane found the USS Yorktown, and shadowed the carrier for the next three hours, guiding the bombers that attacked Yorktown that evening. Two other floatplanes from Chikuma continued to observe the heavily damaged Yorktown through the night, during which time one plane and crew were lost. Chikuma then directed the submarine I-168 to find and attack the Yorktown the following morning.

Chikuma and Tone were then detached to support Vice Admiral Boshiro Hosogaya's Aleutian invasion force. However, the anticipated American counter-attack failed to materialize. CruDiv 8 cruised northern waters uneventfully. Chikuma returned to Ominato port on 24 June.

Rear Admiral Chuichi Hara assumed command of CruDiv 8 from 14 July 1942. With the US invasion of Guadalcanal, Chikuma and Tone were ordered south again on 16 August with the aircraft carriers Shōkaku, Zuikaku, Zuihō, Jun'yō, Hiyō and Ryūjō. They were joined by the battleships Hiei, Kirishima, seaplane tender Chitose, and cruisers Atago, Maya, Takao, Nagara.

Battle of the Eastern Solomons
On 24 August 1942, CruDiv 7's Kumano and Suzuya arrived to join the reinforcement fleet for Guadalcanal. The following morning, a PBY Catalina seaplane spotted Ryūjō, which SBDs and TBFs from Enterprise unsuccessfully attacked. Seven floatplanes from Tone and Chikuma were launched to locate the American fleet. One of Chikuma's planes spotted the Americans, but was shot down before its report could be relayed. However, a second floatplane was more successful, and the Japanese launched an attack against Enterprise, hitting it with three bombs which set her wooden deck on fire. However, in the meantime, the Americans located the Japanese fleet, and Ryūjō was sunk by planes from the USS Saratoga. Chikuma was undamaged in this engagement, and returned to Truk safely.

Through October, Chikuma and Tone patrolled north of the Solomon Islands, waiting word of recapture of Henderson Field by the Japanese.

Battle of Santa Cruz
On 26 October 1942, 250 mi northeast of Guadalcanal, Rear Admiral Hiroaki Abe's task force launched seven floatplanes to scout south of Guadalcanal. They located the American fleet, and Abe followed with an attack which sank the USS Hornet and damaged the USS South Dakota and cruiser USS San Juan. However, Chikuma was attacked by a Douglas SBD Dauntless dive-bomber from Hornet, and quick thinking crewmen jettisoned her torpedoes seconds before a 500-lb. bomb hit her starboard forward torpedo room. She was also hit by two other bombs, destroying one floatplane on the aircraft catapult. Chikuma suffered 190 killed and 154 wounded including Captain Komura.

Chikuma (escorted by Urakaze and Tanikaze) returned to Truk for emergency repairs, and was then sent back to Kure with the damaged carrier Zuihō. During refit and repairs, two additional twin Type 96 25-mm AA guns and a Type 21 air-search radar were added. Repairs were completed by 27 February 1943.

On 15 March 1943 Rear Admiral Kishi Fukuji assumed command of CruDiv 8, and Chikuma was ordered back to Truk. However, on 17 May, Chikuma and Tone were tasked to accompany battleship Musashi back to Tokyo for the state funeral of Admiral Isoroku Yamamoto. Chikuma was back in Truk by 15 July, having avoided numerous submarine attacks along the route.

From July to November, Chikuma was engaged in making troop transport runs to Rabaul, and to patrols of the Marshall Islands in unsuccessful pursuit of the American fleet. While refueling at Rabaul on 5 November 1943, Chikuma and its task force were attacked by 97 planes from the Saratoga, and Princeton. Cruisers Atago, Takao, Maya, Mogami, Agano and Noshiro were damaged. Chikuma, attacked by a single SBD, suffered only near-misses with minor damage.

Back at Kure on 12 December, Chikuma gained additional 25-mm AA guns, bringing its total to 20. CruDiv 8 was disbanded on 1 January 1944, and both Tone and Chikuma were reassigned to CruDiv 7 (with Suzuya and Kumano) under Rear Admiral Shoji Nishimura. Refit completed by 1 February, Chikuma returned to Singapore on 13 February and Batavia on 15 March after a month of raiding commerce in the Indian Ocean. On 20 March 1944, Rear Admiral Kazutaka Shiraishi assumed command of CruDiv 7, and Chikuma was made flagship.

Battle of the Philippine Sea
On 13 June 1944, Admiral Soemu Toyoda activated "Operation A-GO" for the defense of the Mariana Islands. Chikuma was assigned to Force "C" Vice Admiral Jisaburo Ozawa's Mobile Fleet, which proceeded through the Visayan Sea to the Philippine Sea headed towards Saipan. On 20 June, after Haruna, Kongō and carrier Chiyoda were attacked by aircraft from the USS Bunker Hill, USS Monterey and USS Cabot and the bulk of the Japanese air cover was destroyed in the "Great Marianas Turkey Shoot", Chikuma retired with the Mobile Fleet to Okinawa.

After ferrying army troops to Okinawa, Chikuma was reassigned back to Singapore in July, serving as flagship for CruDiv 4 while Atago was under repairs.

Battle of Leyte Gulf
On 23 October 1944, Chikuma (with Kumano, Suzuya and Tone) sortied from Brunei towards the Philippines with Vice Admiral Kurita's First Mobile Striking Force. In the Battle of the Palawan Passage, Atago and Maya were sunk by submarines, and Takao damaged. In the Battle of the Sibuyan Sea the following day Musashi was sunk, Myōkō was crippled and had to be towed to safety, while Nagato and Haruna received damage.

On 25 October, during the Battle off Samar, Chikuma engaged U.S. escort aircraft carriers, helping to sink USS Gambier Bay, but came under fire from the American destroyer USS Heermann and heavy air attack. Chikuma inflicted severe damage on Heermann, but was soon attacked by four TBM Avenger torpedo-bombers, one of which succeeded in hitting her stern port quarter with a Mark 13 torpedo that severed her stern and disabled her port screw and rudder. Chikuma's speed dropped to 18 kn, then to 9 kn, but more seriously, she became unsteerable. At 1105, Chikuma was attacked by five TBMs from USS Kitkun Bay. She was hit portside amidships by two torpedoes and her engine rooms flooded. At 1400, three TBMs from a composite squadron of ships from the USS Omanney Bay and the USS Natoma Bay led by Lt. Joseph Cady dropped more torpedoes which hit Chikuma portside. Cady was later awarded the Navy Cross for his action. It is generally thought that destroyer Nowaki took off survivors from Chikuma, and then scuttled her at 11.41667°N, 126.6°W in the late morning of on 25 October 1944, but a more recent study suggests Chikuma sank from the effect of the air attack, and Nowaki only arrived in time to pick up survivors from the water.

On 26 October 1944, Nowaki was sunk by gunfire from USS Vincennes, USS Biloxi and USS Miami and DesDiv 103's USS Miller, USS Owen and USS Lewis Hancock. It sank 65 mi SSE of Legaspi, Philippines with about 1,400 men including all but one of Chikuma's surviving crewmen.

Chikuma was removed from the navy list on 20 April 1945.