The Battle of Tokyo Bay

Late in the evening of 22 July 1945 nine American destroyers slipped in darkness into the waters between the Bōsō Peninsula and Sagami Bay, at the very entrance to Tokyo Bay. In the minutes before and just after midnight the ships of Destroyer Squadron 61 shelled and torpedoed a small Japanese convoy sailing along the coast. The action lasted less than half an hour; one freighter sank, another was badly damaged, and the Americans withdrew without loss. It is sometimes called the last surface battle of the Second World War.

The entry found in war chronologies – “America and Japan fight a small skirmish in the Battle of Tokyo Bay; the Japanese suffer light losses” – needs two qualifications. The fighting did not take place in Tokyo Bay itself but in its approaches, a few nautical miles south-west of Cape Nojima at the tip of the Bōsō Peninsula; in English-language literature the action appears more often as the Battle of Sagami Bay, although some American accounts use the name “Tokyo Bay”. Nor was it so much a clash between two fleets as a destroyer raid on a weakly escorted convoy: the Japanese escorts did not join battle, and all the losses were on the Japanese side.

The fleet off the coast of Japan

In the summer of 1945 the US Navy was able, for the first time in the war, to operate right off the coasts of the Japanese home islands. After the fighting on Okinawa ended, Admiral William Halsey’s Third Fleet left Leyte Gulf at the beginning of July, and from 10 July, when its carriers struck the airfields around Tokyo, it waged an unbroken campaign against Japan. The fast carriers (Task Force 38) were commanded by Vice Admiral John S. McCain; from mid-July a British carrier force operated alongside them.

Unlike the February carrier raids on Tokyo, flown before the landing on Iwo Jima, the July operations were no brief raid. Aircraft attacked airfields, ports, shipyards and railways, while heavy ships bombarded the coast: on 14 July battleships shelled the works at Kamaishi – the first bombardment of the Japanese home islands by surface ships in the war – on 15 July the steelworks at Muroran on Hokkaido, and on the night of 17–18 July, with a British battleship taking part, the area around Hitachi. According to American accounts, on the night of 18–19 July cruisers and destroyers, having found no shipping at sea, shelled the radar station on Cape Nojima – to meagre effect.

Japan no longer had a fleet capable of opposing such forays. Its surviving battleships and carriers lay in port, short of fuel and largely without aircraft, and coastal shipping was protected by a handful of minesweepers, submarine chasers and small escorts. The July campaign also fell in the stormy season: the fleet still remembered June’s Typhoon Connie, and in the days before the raid another typhoon passed nearby.

The sortie of Destroyer Squadron 61

Destroyer Squadron 61, commanded by Captain Thomas H. Hederman, formed part of the screen of McCain’s carriers. It consisted of nine new Allen M. Sumner-class destroyers: the flagship USS De Haven and Mansfield, Lyman K. Swenson, Collett, Maddox, Blue, Brush, Taussig and Samuel N. Moore. The squadron was detached from the main force with orders to sweep Sagami Bay and the approaches to Tokyo Bay in search of Japanese shipping – according to American naval historians, one of the deepest penetrations of Japanese coastal waters up to that time.

According to Japanese studies, the ships left the carrier group on the morning of 21 July and headed for the coast of Honshu in poor, stormy weather. By the next day the typhoon had passed, but the sea was still running high. On the evening of 22 July the destroyers, in column, increased speed and began the final leg of their run. At about 11.05 p.m., at 24 knots, De Haven’s radar picked up a surface contact at about 19 nautical miles, and a dozen or so minutes later the fire-control radars distinguished four vessels.

It was a small Japanese convoy that had left the bay at Tateyama at 9 p.m., bound north for Hakodate. It consisted of two merchant ships – the Enbun Maru of the Nippon Yūsen line, of 6,919 tons, and the small 800-ton Hakutetsu Maru No. 5 – escorted by Minesweeper No. 1 and Submarine Chaser No. 42. According to Japanese sources, the Enbun Maru was carrying more than 7,000 tons of machine tools from factories being relocated to Manchuria, as well as eight landing barges; the cargo was to go via Hakodate to the Korean port of Rasŏn.

Half an hour of fire

The Americans increased speed to 27 knots and, wary of Japanese torpedoes, closed to about 10 km. According to the Japanese account, at about 11.50 p.m. each destroyer fired two torpedoes, after which the ships opened fire with their 5-inch (127 mm) guns; American accounts place the start of the attack just after midnight. The convoy was then about 4.5 nautical miles south-west of Cape Nojima and, it seems, expected nothing. Shells from the first salvoes hit both merchant ships, which caught fire. At about 12.05 a.m. the destroyer crews heard several explosions from the direction of the Hakutetsu Maru and concluded that at least two torpedoes had struck her.

The Japanese escorts – as sailors from the Enbun Maru later testified – sheltered behind the freighter’s hull and did not join battle. The Enbun Maru herself returned fire with the gun and machine guns she had been armed with, and the Americans also recorded fire from coastal batteries on Cape Nojima; no American ship was hit. Japanese documents also speak of air attacks, which American records do not confirm. At 12.09 a.m. on 23 July Hederman broke off the attack, and the squadron turned and withdrew from the coast. The only trouble on the way back was a steering failure on Brush; that evening the destroyers rejoined the carriers. According to American tallies they had expended 3,291 5-inch shells and 18 torpedoes.

The outcome

Japanese losses proved smaller than the Americans believed; they claimed to have sunk two transports – one medium and one small – and damaged another ship and one of the escorts. According to Japanese sources, only the Hakutetsu Maru No. 5 sank, and only while under tow to Yokosuka, together with her entire cargo. The crew of the Enbun Maru managed to put out the fires, and the ship and her escorts took refuge in the bay at Tateyama. She was nonetheless badly damaged – her bridge among other things was wrecked – and according to the owner’s war history five crew members were killed, including the master, and seven wounded (one of whom later died); there were also casualties among the soldiers serving on board. The voyage was abandoned and the cargo never reached Korea. The minesweeper and the submarine chaser came out of the action undamaged.

The phrase “light losses” is therefore accurate in terms of the scale of the war – one small ship, a dozen or so casualties – but it does not convey how one-sided the action was: the Americans lost not a single man, and the Japanese could not even get close to their attackers.

The last surface battle

The action of the night of 22–23 July is regarded as the last surface battle of the Second World War – if the Soviet operations off the coasts of Korea, Sakhalin and the Kurils in August are left aside. Japanese authors point out that the title is also given to other engagements: the sinking of the cruiser Haguro by British destroyers in May 1945, or a skirmish between junks off the coast of China after the surrender had already been announced. The argument is a secondary one, however: by the summer of 1945 the Japanese navy was no longer capable of fighting a battle against an enemy fleet, and naval engagements came down to hunting the remnants of its shipping.

Significance

Militarily, the sortie of Destroyer Squadron 61 was of secondary importance – the sinking of one small freighter changed nothing in the position of Japan, whose shipping had for months been ravaged by submarines, aircraft and mines dropped by B-29s. The event’s message was different: American destroyers had operated unhindered at night a few miles off Honshu, at the entrance to the bay on which lay Tokyo, Yokohama and the naval base at Yokosuka, and had returned without a single hit.

The Third Fleet’s July offensive continued. On 24 and 28 July aircraft from Halsey’s carriers and the British force struck the base at Kure, where the last major warships of the Japanese navy lay, and on the night of 29–30 July battleships shelled Hamamatsu. The American command also treated these operations as preparation for the planned invasion of the home islands – Operation Downfall, whose first stage was to be a landing on Kyushu in the autumn of 1945. The invasion never took place: in August the war was ended by the atomic bombs, the Soviet Union’s entry into the war against Japan and the Emperor’s decision to surrender, and the ships that in July had crept up to Cape Nojima by night sailed into Tokyo Bay a few weeks later as part of the occupation fleet.