The Matsu-class destroyers (松型駆逐艦, Matsu-gata kuchikukan) were a class of destroyer built for the Imperial Japanese Navy (IJN) in the late stages of World War II. The class was also designated the Type-D Destroyer (丁型駆逐艦, Tei-gata kuchikukan). Although sometimes termed Destroyer escorts, they were larger and more capable than contemporary United States Navy destroyer escorts or the Imperial Japanese Navy kaibōkan vessels.^[5]

Even by 1942, the Imperial Japanese Navy General Staff realized that attrition of its destroyer force was not sustainable. There was a growing need for a simplified design which could be quickly mass-produced, and which could serve primarily as convoy escorts and as destroyer-transports in front-line locations, but would still be capable of working with the fleet if necessary. Emphasis was placed on anti-aircraft guns and anti-submarine weapons, and radar, as operations against surface targets was deemed unlikely. Forty-two vessels were ordered and work began in August 1943.

In the middle of 1944, the orders for twenty-four of these vessels were replaced with a further-simplified design, designated the Tachibana-class destroyer (橘型駆逐艦, Tachibana-gata kuchikukan) or Modified Type-D Destroyer (改丁型駆逐艦, Kai Tei-gata kuchikukan). The Tachibana-class had straight lines and a modular construction to facilitate mass-production. The Imperial Japanese Navy had plans to build another hundred and twelve Tachibana-class vessels, but only fourteen were completed before construction was cancelled, with resources diverted to "special-attack units".^[5]

Designed for ease of production, the Matsu class was smaller, slower and more lightly armed than previous destroyers as the IJN intended them for second-line duties like escorting convoys, releasing the larger ships for missions with the fleet.^[6] The ships measured 100 meters (328 ft 1 in) long overall, with a beam of 9.35 meters (30 ft 8 in) and a draft of 3.3 meters (10 ft 10 in).^[7] Their crew numbered 210 officers and enlisted men.^[8] They displaced 1,282 metric tons (1,262 long tons) at standard load and 1,554 metric tons (1,529 long tons) at deep load.^[9] The ships had two Kampon geared steam turbines, each driving one propeller shaft, using steam provided by two Kampon water-tube boilers. The turbines were rated at a total of 19,000 shaft horsepower (14,000 kW) for a speed of 27.8 knots (51.5 km/h; 32.0 mph). The Matsus had a range of 4,680 nautical miles (8,670 km; 5,390 mi) at 16 knots (30 km/h; 18 mph).^[10]

The main armament of the Matsu-class ships consisted of three 127-millimeter (5 in) Type 89 dual-purpose guns in one twin-gun mount aft and one single mount forward of the superstructure. The single mount was partially protected against spray by a gun shield. The accuracy of the Type 89 guns was severely reduced against aircraft because no high-angle gunnery director was fitted. The ships carried a total of 20 Type 96 25-millimeter (1 in) anti-aircraft guns in four triple and eight single mounts. The Matsus were equipped with a Type 22 surface-search radar.^[11] The ships were also armed with a single rotating quadruple mount amidships for 610-millimeter (24 in) torpedoes. They could deliver their 36 depth charges via two stern rails and two throwers.^[7][11]

The early ships of the class probably were not initially fitted with a Type 13 early-warning radar. The radar and five additional 25 mm guns on single mounts were generally installed in late 1944.^[11]

The Tachibana-class, entering service in 1945, had the same armament as the Matsu-class, but initially with 13 single-mount Type 96s instead of eight. This was later increased to as many as 19. Only one vessel, Take, was modified to launch a single kaiten manned torpedo from her stern, although there were plans to covert another 11 to this configuration just before the war came to an end.^[5]

Matsu-class destroyers were assigned to Destroyer Divisions 43, 52, and 53. Few Matsu-class units saw extensive service beyond Japanese home waters, and none of the Tachibana-class.^[5]

Forty-two vessels were ordered in Fiscal Year 1943 under the Modified 5th Naval Armaments Supplement Programme as #5481-#5522. Eighteen of these were completed to the original Matsu design, but the other twenty-four were altered to a modified (simplified) design which became known as the Tachibana class. Eight of this batch were completed to that design, while orders for sixteen were subsequently cancelled (of which eleven had not been laid down).

Another thirty-two vessels were authorised in Fiscal Year 1944 under the Wartime Naval Armaments Supplement Programme as #4801-#4832, all to the Tachibana design. Six of this batch were completed to that design, while another four were ordered and laid down but were subsequently cancelled on 17 April 1945; the remaining twenty-two were never ordered.

A further eighty vessels were projected in Fiscal Year 1945 to a further modification of the design, known as the Kai-Tachibana class, but no orders were placed before the end of the war brought an end to the programme.