Kinashi was a native of Usuki in Ōita Prefecture. His early career was not promising, as he graduated in very last place as 255th of 255 cadets in the 51st class of the Imperial Japanese Navy Academy in 1920. He served his midshipman duty on the cruisers, Tatsuta, and on on its long distance navigational training voyage to Hilo, Acapulco, Balboa, San Francisco, Vancouver, Honolulu, Jaluit Atoll, Truk, Saipan and the Ogasawara Islands from 1924-1925. He was promoted to ensign during the voyage, and on his return to Japan, he completed naval artillery and torpedo warfare training. He was assigned to the destroyer Harukaze and promoted to sub-lieutenant in December 1926. In 1927, Kinashi transferred to the Japanese submarine forces. He was promoted to lieutenant in November 1929 and served in various capacities on,,, and the river gunboat, and destroyer Fubuki through the mid-1930s. He was promoted to lieutenant commander in December 1937, and assigned to the minelayer. Kinashi was given his first command,, from 1938-1940. In 1940, he was reassigned to the Submarine Warfare School, but returned to sea six months later as captain of from July–November, and of from November 1940 to July 1941. At the time of the attack on Pearl Harbor, Kinashi was captain of. He was captain of for one month before being reassigned to. On September 15, 1942, while patrolling south of the Solomon Islands during the Guadalcanal campaign, I-19 sighted and attacked the American aircraft carrier, which was part of a task force transporting the 7th Marine Regiment and stores to Guadalcanal. Kinashi penetrated the destroyer screen, and after closing to within 500 meters of the aircraft carrier, launched his full salvo of six torpedoes. Three torpedoes struck Wasp, starting uncontrollable fires which soon forced the abandonment of the ship. The remaining three torpedoes continued beyond the horizon for another twelve miles into a separate task force led by the, striking the battleship and destroyer O'Brien sank several weeks later and North Carolina was so severely damaged that it was out of commission for several months for repairs. Kinashi was promoted to commander less than two months later, and honored with a personal interview with Emperor Hirohito. On May 2, 1943, while near Suva, Fiji, I-19 under the command of Kinashi torpedoed the liberty shipWilliam Williams. However, for unknown reasons, Kinashi chose not to finish off the heavily damaged ship, which was later towed to New Zealand and repaired, becoming the. From October 1943, Kinashi was captain of. On December 17, 1943, I-29 was dispatched on a secret Yanagi mission under the Axis Powers' Tripartite Pact to provide for an exchange of personnel, strategic materials and manufactured goods between Nazi Germany and the Empire of Japan. At Singapore she was loaded with 80 tons of raw rubber, 80 tons of tungsten, 50 tons of tin, two tons of zinc, and three tons of quinine, opium and coffee. In spite of AlliedUltra decrypts of her mission, I-29 managed to reach Lorient, France on March 11, 1944. While his crew rested in France, Kinashi travelled on to Berlin where he was awarded the Iron Cross2nd class personally by Adolf Hitler for his role in sinking Wasp. I-29 left LorientApril 16, 1944 with a cargo of 18 passengers, torpedo boat engines, Enigma coding machines, radar components, a Walter HWK 509A rocket engine, and Messerschmitt Me 163 and Messerschmitt Me 262 blueprints for the development of the rocket planeMitsubishi J8M, returning at Singapore on July 14, 1944. On the way back to Kure, Japan, I-29 was attacked at Balintang Channel, Luzon Strait near the Philippines by Commander W. D. Wilkins' "Wildcats" submarine taskforce consisting of, and, using Ultra signal intelligence. During the evening of July 26, 1944, I-29 was hit by three torpedoes fired by Sawfish. I-29 sank immediately at. Kinashi was posthumously promoted two levels in rank to that of rear admiral.
