Ships
- IJN Tone Captain from 10 September 1941
Tametsugu Okada was born in Nara Prefecture on 19 February 1895 and spent his career in the Imperial Japanese Navy. He finished the Imperial Naval Academy in November 1917, seventeenth in a class of eighty-nine, and was commissioned an ensign in August 1918. He passed through the advanced course at the Naval Gunnery School. As a lieutenant he served as a division officer in the battleship Hiei, spent a period of duty in Germany, and later held a gunnery division billet in the heavy cruiser Aoba.
In November 1930 he graduated from the Naval War College. Staff appointments followed with the First Destroyer Squadron and with Cruiser Division 11, and he also served on the Naval General Staff. Promoted commander in November 1934, he was executive officer of the light carrier Ryujo from December 1937 to December 1938. He became a captain on 15 November 1938. His first command was the minelayer Yaeyama, from December 1938 until October 1939. He then returned to Tokyo as a section chief on the Naval General Staff and as a naval staff officer at Imperial General Headquarters.
On 10 September 1941 Okada took command of the heavy cruiser Tone. She was the name ship of a class built to scout for the carriers, with her eight-inch guns grouped forward and a long aircraft deck aft, and she operated beside her sister Chikuma in Cruiser Division 8. Late in November the division left Hitokappu Bay in the Kuriles with Vice Admiral Chuichi Nagumo's striking force. On the morning of 7 December 1941 Tone sent a floatplane over Lahaina Roads, which found no American warships in the anchorage, and launched another aircraft to patrol south of the carriers. One of her planes capsized and was lost while landing back aboard in a heavy swell.
Okada kept Tone with the carrier force through the first half of 1942. The cruiser went to the second attack on Wake, screened the raid on Darwin, and entered the Indian Ocean in the spring, when her floatplanes searched ahead of the carriers for British ships. In June she was with Nagumo at Midway. A floatplane from Tone, launched late, reported the American carrier force, and that contact reached the flagship while the Japanese squadrons were still changing between bombs and torpedoes. Okada left the cruiser on 14 July 1942. Later captains of Tone included Haruo Mayuzumi and Yusaku Okada, another officer of the same surname.
After a short attachment to the Yokosuka Naval District, Okada became commanding officer of the carrier Junyo on 20 July 1942. In October, serving under Rear Admiral Kakuji Kakuta of the Second Carrier Division, Junyo took part in the Battle of the Santa Cruz Islands, and her aircraft joined the attacks on the American carriers. In February 1943 he moved to Shokaku, which had been heavily damaged by bombs in that battle and was coming back into service. He commanded her into November 1943 and was promoted rear admiral on 1 November 1943.
On 30 November 1943 he became chief of staff of the Fourth Southern Expeditionary Fleet, the naval command based at Ambon for the eastern Netherlands East Indies, and he held that post until 10 March 1945. His final rank was rear admiral. He died on 3 September 1947.