Kashii was the third Katori-class training cruiser and was named for the Kashii Shrine in Fukuoka. Mitsubishi laid her down at Yokohama on 30 May 1940 and launched her on 14 February 1941, and she was completed on 15 July 1941. Captain Sanji Iwabuchi, later the admiral who died defending Manila, had been her chief equipping officer. Captain Hideo Kojima took command on 15 October 1941. Three days later she was at Saigon as flagship of Vice Admiral Jisaburo Ozawa's Southern Expeditionary Fleet.
On 5 December 1941 she left Cape St. Jacques with seven transports carrying the Army's 143rd Infantry Regiment, and on 8 December the troops landed at four points on the Kra Isthmus in Thailand. Through December she escorted the second and third Malaya convoys, and in February 1942 the convoy for Bangka and Palembang in Sumatra. In March she and Yura escorted the landings in northern Sumatra, and then she helped escort the first troop convoy to Rangoon, which arrived on 23 March. In April she escorted the 18th Division toward Penang. From 11 April 1942 she was flagship of the First Southern Expeditionary Fleet at Singapore and served there as guardship. Captain Kazue Shigenaga took command in June 1942 and Captain Satoshi Takada in January 1943. On 29 August 1943, off Pulo Weh in northern Sumatra, HMS Trident fired eight torpedoes at her and missed.
Early in 1944 she was briefly a training ship for the Naval Academy at Etajima. Then she was rebuilt at Kure as an antisubmarine ship. Her torpedo tubes came off, and twin 127-millimeter mounts, more 25-millimeter guns and depth charges went on. Captain Midori Matsumura took command on 5 March. From May 1944 she led convoy escort groups on the run between Moji, Manila and Singapore, the tanker route on which Japan's war now depended. In convoy HI-74, sailing from Singapore in September 1944, she was flagship of Rear Admiral Setsuzo Yoshitomi's 5th Escort Group. On the night of 16–17 September Queenfish torpedoed a tanker in the convoy and Barb torpedoed the escort carrier Unyo, which sank that morning. The Tabular Record counts more than 900 men lost with her.
On 9 January 1945 Kashii left Saigon as flagship of Rear Admiral Shiro Shibuya's 101st Escort Group, with convoy HI-86 of four tankers and six cargo ships. That week Task Force 38 had come into the South China Sea. On 12 January, off the coast of Indochina after the convoy left Qui Nhon, aircraft of Task Group 38.3 from Essex, Ticonderoga, Langley and San Jacinto attacked from 1100 to 1700. They sank most of the convoy or drove the ships ashore, and only three escorts survived. At 1408 Kashii was hit amidships on the starboard side by a torpedo, and a Helldiver put two bombs aft that set off her depth-charge magazine. She sank stern first. 621 men went down with her and 19 were rescued. Captain Matsumura and Rear Admiral Shibuya were both killed and were promoted after death. She was struck from the Navy List on 20 March 1945.
A note on sources. This history follows the Tabular Record of Movement for Kashii by Bob Hackett and Sander Kingsepp at combinedfleet.com, and the list of captains in the Japanese Wikipedia article on Kashii. The record names the carriers of Task Group 38.3 as the attackers. The caption of the Navy photograph of her sinking, 80-G-300684, says it was taken from an aircraft of Hancock, a carrier the record does not name among the attackers. Which carriers' aircraft hit her is not settled here.
