Asahi-class destroyer

JS Shiranui (DD-120)
Class overview
Builders	Mitsubishi Heavy Industries
Operators	Japan Maritime Self-Defense Force
Preceded by	Akizuki class
Cost	DD119: JPY72.3 billion[1] $893 million (constant 2009 USD)
Built	2015–2019
In service	2018-present
In commission	2018–present
Completed	2[2]
Active	2
General characteristics
Type	Destroyer
Displacement	5,100 t (5,000 long tons) standard 6,800 t (6,700 long tons) full load
Length	151 m (495 ft 5 in)
Beam	18.3 m (60 ft 0 in)
Draft	5.4 m (17 ft 9 in)
Depth	10.9 m (35 ft 9 in)
Propulsion	COGLAG, two shafts, two GE LM2500 turbines
Speed	30 knots (56 km/h; 35 mph)
Complement	230
Sensors and processing systems	OYQ-13 ACDS FCS-3A AAW system OPY-1 AAW system OQQ-24 ASW system OQR-4 Towed sonar array system NOLQ-3D-2 EW system OPS-48 surface search radar
Armament	1 × Mk. 45 Mod 4 127 mm (5 in)/62 gun 8 × Type 90 Anti-ship missile in quad canisters 2 × 20 mm Phalanx Block1B CIWS 2 × HOS-303 triple 324 mm (12.8 in) torpedo tubes Anti-torpedo System 32-cell Mk. 41 Vertical launching system RIM-162 ESSM SAM RUM-139 VL-ASROC Type 07 VL-ASROC
Aircraft carried	1 × SH-60K helicopter

The Asahi class of destroyers is a class of warships of the Japan Maritime Self-Defense Force. The Asahi is largely based on the Akizuki-class destroyer; while the Akizuki-class specialized in anti-air warfare, the Asahi-class was designed to specialize in anti-submarine warfare. The design was initially designated "25DD", referring to a date on the Japanese calendar, specifically the 25th fiscal year of the Heisei period (2013), the year that procurement of the class began.

The lead ship, Asahi, is the third ship to hold the name after the Asahi-class destroyer escort lent from the United States Navy in 1955, and the Imperial Japanese battleship. The second ship of the class, Shiranui, is the third ship to hold its name after the Murakumo and Kagerō-class destroyers.

The procurement of the destroyer began in 2013 in response to the reduction in the number of destroyers (namely the Hatsuyuki class) within the JMSDF. The two major characteristics of this destroyer is its bigger emphasis on anti-submarine warfare and the adoption of a COGLAG (combined gas turbine electric and gas turbine: a modification of the combined gas and gas propulsion system employing electric propulsion system for low-speed cruising) propulsion system. A second destroyer was procured a year later.^[3][4]

The Asahi class is based on the existing Akizuki-class destroyer to reduce acquisition cost and allow future development and growth. Unlike the Akizuki class, which focuses on anti-aircraft warfare, the Asahi class focuses on anti-submarine warfare.^[5]

The Asahi class is the first class of Japanese warships to be equipped with a COGLAG propulsion system, allowing the class to be more fuel efficient than previous warships. Another unique feature of this destroyer is the usage of a GaN-AESA (gallium nitride - active electronically scanned array) multifunction radar. The Asahi class is the second Japanese class of warship to be outfitted with this technology (the Akizuki class was the first). The destroyer's radar is based on the FCS-3A radar used for the Akizuki class and uses gallium nitride to improve performance.^[5] In radar technology, gallium nitride offers a number of advantages over the typically used gallium arsenide (GaA). These advantages include higher power density, efficiency, thermal spreading and frequency coverage. In turn, this allows the GaN chip to be smaller than their GaA counterpart, thus reducing cost and increasing overall cost effectiveness.^[6]