Ships
- IJN I-168 (I-168) Captain from 31 August 1942
Katsuji Watanabe (渡辺勝次) was an officer of the Imperial Japanese Navy, a graduate of the fifty-fifth class of the Naval Academy at Etajima, from Saga Prefecture, who spent nearly the whole of his seagoing career in submarines. He commanded the old destroyer Kuri briefly in 1939–40, the small submarines RO-67, RO-33 and RO-34 in 1940–41, and from 31 July 1941 to 5 April 1943 the cruiser submarine I-69, renamed I-169 in May 1942. In her he lay off Pearl Harbor on the night of the attack, shelled Midway, took part in the Midway operation, sank a Dutch freighter off New Caledonia and carried supplies to Kiska in the Aleutians. He then commissioned a new submarine, I-40. On 22 November 1943 I-40 left Truk to meet the American invasion of the Gilbert Islands and was never heard from again. He was a lieutenant commander when he took I-169, a commander from 1 November 1943, and is recorded as a captain on the date the Navy declared his boat lost.
The Navy's rosters give his home as Saga Prefecture, in Kyushu, and the middle school he attended as Saga Middle School. His date of birth, his parents and any family of his own are not recorded in any source that could be examined.
He entered the Naval Academy at Etajima, the island school on the Inland Sea where the Navy trained its officers, and graduated with the fifty-fifth class on 28 March 1927. The class had 120 graduates, and the personnel summary places him 38th among them. As a midshipman he was assigned to the light cruiser Abukuma. On 25 May 1928 he was attached to the Yokosuka naval depot, and he became an ensign on 1 October 1928, a lieutenant (junior grade) on 1 December 1930 and a lieutenant on 15 November 1933.
On 18 July 1934, as a lieutenant, he became navigating officer of the submarine I-53, which marks his entry into the submarine branch. He then served in the crew of the small submarine RO-67 and, from 1 December 1936, studied in the Submarine School's course for junior officers. The summary places him on the Kure Naval District's roll from 20 March 1937 and records that he was torpedo officer of the submarine I-5 in the period up to 20 October 1939.
His first command was a destroyer. On 1 November 1939, as a lieutenant, he was appointed captain of Kuri, a Momi-class destroyer completed in 1920 and by then an old ship. Two weeks later, on 15 November 1939, he was promoted lieutenant commander, and Kuri was placed in the 13th Squadron of the China Area Fleet, formed that day. He held the post for four months, until 1 March 1940, and the sources examined say nothing of what the ship did while he commanded her. His career returned to submarines at once. On 20 March 1940 he took command of the small submarine RO-67, and on 30 October 1940 of RO-33, which was in the 21st Submarine Division of the 4th Submarine Squadron. In May 1941 RO-33 and her sister RO-34 were placed in reserve at Sasebo; on 1 July he was given RO-34 as an additional duty, and a month later, on 31 July 1941, he left both for a larger boat.
The boat was I-69, a cruiser submarine of the sub-class the Navy called KD6, completed in 1935 and belonging to the 12th Submarine Division. He joined her on 31 July 1941, four months before the war. In November the division, with I-68 and I-70, was assigned to the Sixth Fleet's Advanced Expeditionary Force for the attack on Pearl Harbor. I-69 left Saeki on 11 November with the division commander, Captain Nobuki Nakaoka, aboard, put in at Kwajalein, and sailed for Hawaii.
Her assignment was to lie off the entrance of Pearl Harbor with I-68 and wait for the crews of the midget submarines sent into the harbour. According to the tabular record built from Japanese sources, Watanabe saw at 9.01 p.m. on 7 December "a massive explosion in Pearl Harbor", followed by several more and high columns of fire, and judged that it must have been some capital ship sunk by the midget submarines. Later that night I-69 found a destroyer south-south-east of Barbers Point and fired a torpedo at her. The destroyer turned away and I-69 was depth-charged. On 8 December she waited off the entrance, and none of the midget submarines returned. On the 9th she made an unsuccessful attack on a cargo ship south of Oahu and was depth-charged, and she then became entangled in an anti-submarine net off Barbers Point. The crew struggled for hours to free her, did so at the cost of a damaged periscope, and remained submerged for about thirty-nine hours before the hope of rescuing downed aircrew was abandoned. She returned to Kwajalein on 27 December.
In January 1942 she was sent to Midway. She arrived off the atoll on 21 January. At about 6.05 p.m. on 8 February she surfaced less than a thousand yards south of the mouth of Brooks Channel and fired her 10-centimetre gun at the radio station on Sand Island; one shell struck a concrete ammunition magazine, and the island's five-inch battery fired back after three rounds had been fired, forcing her down. On 10 February she tried again and was seen at once by two Marine Brewster fighters on patrol, whose bombs, according to the American records the tabular record follows, were near misses; she was strafed before she could submerge. She returned to Kwajalein on 17 February, sailed on 18 February for a third patrol, and was diverted to the waters east of Wake after the American carrier raid on Rabaul was called off. After an overhaul at Kure she made a fourth patrol in the Wake area from 15 April to 9 May. On 20 May 1942, in the Navy's general renumbering of its large submarines, she became I-169.
In the Midway operation she sailed from Kwajalein on 24 May with the 3rd Submarine Squadron's "A" group of five boats and took station on a line in the American reinforcement route from Hawaii, arriving on 31 May and returning to Kwajalein on 20 June. She sighted no target recorded in the sources. On 9 July, with the new division commander, Captain Yoshisuke Okamoto, aboard, she left Kwajalein to reconnoitre New Caledonia and the New Hebrides. She scouted the Bay of St. Vincent, and in late July, seventy-five miles south-east of Nouméa, she torpedoed the Dutch steamer Tjinegara, a ship of 9,227 tons being used as an American army transport, which sank after several hits. On 4–5 August she reconnoitred Port Vila on Efate, was chased by two destroyers, and was damaged in her main ballast tanks. She reached Truk on 15 August and Kure on 24 August, and went into the yard at Sasebo for an overhaul on 2 September. From 31 August to 15 October 1942 Watanabe was also, as an additional duty, captain of her sister I-168, then under repair; that boat had sunk the carrier Yorktown at Midway in June, under another commander. On 18 September I-169 reached Truk, to join the submarine squadrons operating around Guadalcanal. On 16 November the submarine commander at Truk told his captains that the force had been ordered to organize a supply system for the army garrison on the island; the sources examined record no supply run by I-169. She returned to Kure on 3 January 1943.
The winter and spring of 1943 were spent in the Aleutians. She left Kure on 15 February carrying a Type A midget submarine, its torpedoes and soldiers of the army, for Kiska; she arrived on 26 February, unloaded and left the next day. She then patrolled toward Amchitka, where, in the Naval Data Base's account, she escaped a depth-charge attack by a force of cruisers she had sighted. On 13 March, at half past four in the afternoon, she entered Kiska again and took on board passengers and the remains of thirty-three men. She called at Attu, then at Paramushiro in the Kuriles from 17 to 22 March, where the tanker Teiyo Maru refuelled her; she took station on a patrol line south of Adak on 25 March and left it on the 28th. After another call at Kiska on 1 April, Watanabe was relieved on 5 April 1943 as captain by Lieutenant Commander Zenshin Toyama. He had commanded her for just over twenty months, through seven numbered war patrols, and she had carried him from a rescue station at Pearl Harbor to the edge of the Bering Sea. No account by him of any of these patrols has been found.
His next assignment was a new boat. On 10 May 1943 he was appointed chief equipping officer of I-40, a cruiser submarine of an improved type building at Kure; she was launched on 10 November 1942 and completed on 31 July 1943, when he became her captain. The new boat was assigned to the 11th Submarine Squadron for working up. In August, in the Inland Sea off Kure, she took part in trials of a new Type 3 sonar and a magnetic anomaly detector, both used in hunting submarines, with the minelayer Nuwajima, and her part was to be the target. On 31 October the boat was reassigned to the 2nd Submarine Division of the 1st Submarine Squadron, Sixth Fleet, and on 1 November he was promoted commander. She left Yokosuka for Truk on 13 November and arrived on the 19th.
The next day, 20 November 1943, American forces invaded Tarawa and Makin in the Gilbert Islands. The commander of the Sixth Fleet, Vice Admiral Takeo Takagi, ordered every submarine within reach to the area, among them I-40 and I-169, now under another commander. I-40 left Truk for the Makin area on 22 November on her first war patrol. On 26 November Takagi ordered I-19, I-40, I-169 and RO-38 to form a picket line north of Makin. On 2 December Sixth Fleet headquarters asked I-40, I-19 and I-20 where they were, and I-40 gave no reply. She carried 97 men.
On 21 February 1944 the Navy declared I-40 lost in the Gilberts area, with all hands, and it recorded Watanabe as dead with the rank of captain. The boat was struck from the Navy List on 30 April 1944. No American attack on her has been identified. Several accounts name the destroyer Radford, alone or with land-based aircraft, as her killer in late November 1943; another proposes the destroyer Boyd on 23 or 26 November, in an action usually credited with the sinking of I-39; and the Japanese Wikipedia observes that the Americans have no record of sinking her and that an accident cannot be excluded. No wreck has been identified. The boat Watanabe had commanded for twenty months, I-169, was lost at Truk on 4 April 1944 under a later commander. She dived at anchor during an air raid with a ventilator valve open and flooded; 103 of her crew died, and 21 men who were ashore survived. Her wreck was found in 1972, and the remains of her crew were brought home the next year.
Nothing is recorded of his wife or children, if he had any, his age at death, or any memorial to him. What survives is a career that can be followed in submarines from 1934, a class standing of 38 among 120, and a war record that ends in a silence on the radio on the way to Makin, with 97 men aboard.