JMSDF (Cold War Japanese Navy)

The Japanese Navy in 1945:

Of the immense fleet of the Second World War, the third largest in the world, only minor units remained. The steamer of the US Navy had rolled its manpower whose last units were deprived of fuel and immobilized. It was these last ships that survived the air raids that formed the basis of the new Japanese self-defense force under the authority of Douglas MacArthur, with a focus on the major geostrategic issue of the Soviet Pacific fleet.

As a result, far from being a modest fleet of coast guards and fishery guardians, the new JMSDF eventually had an impressive potential. Currently, the Nippon Navy ranks just third, behind the former Soviet fleet, and in front of the British fleet, a level it could never reach in the days of militarism and virulent nationalism. Strange destiny for a “self-defense” force…

Haruna and Lake Champlain

The remains of “Nihon Kaigun” in 1945:

Of the huge fleet of 1941, there were no longer any ships of the line, nor cruiser, and only three destroyers, class Akizuki, and two carriers, the old Hosho (1922), demobilized, and the Katsuragi, well more recent (1944). These five units were taken into account by the new Ministry of the Navy, the second ministry of demobilization.

These ships for a few years skim the islands of the Pacific to bring home isolated Japanese garrisons. They were later retired in 1947 and demolished. The remainder of these surviving numbers consisted of coastal and light units, 53 minesweepers, former wooden submarine hunters (Cha type), and 12 light patrol boats, designed to serve as post-war trawlers.

They were assisted by high-sea patrol boats (Ukuru class) serving as supply vessels. The main role they were given was to clear Japanese waters of the 100,000 mines originally intended to block a US landing in January 1946. This force was incorporated into what was then known as the Maritime Safety Agency with two sections and to their heads, Admiral Yashio Yamamoto and Captain Tamura.


Under Article 9 of the new constitution, no military intervention force could be mobilized and the right to armed action to settle a different international could not be tolerated. However, from that time this principle was amended, if it were not to allow Japan, a maritime power, to guard its territorial waters and exercise a police role of traffic and fishing, but also later to face the Soviet threat.

By the time the Japanese shipyards, largely bombed and devastated, were again operational, the US Navy transferred some vessels to the JMSDF (Japanese Maritime Self Defense Force), which was founded in 1954. The maritime security agency became the main force. of Japanese Coast Guard, modeled on the US Coast Guard. From this date, the reorganized shipyards would be able to build a fleet of larger units.

JMSDF 1960

Balance sheet for 1960:

-19 Destroyers:
The big Akizuki (1941) having been scrapped there was only the only Wakaba, ex-Nashi, an escort destroyer of the class Tachibana (1945). It remained in service until 1972. Soon the US Navy transferred two Benson / Gleaves class destroyers in 1954 (Asakaze and Hatakaze) and two others of the Fletcher class (Ariake and Yugure). They remained in operation until 1969 and 1974 respectively. The shipyards then issued the first class of Japanese post-war destroyers, the Harukaze. To these two ships succeeded the 7 Ayanami, heavier, then the 3 Murasame and the two Akizuki. All were in service in 1960. They were classic buildings with artillery.

-23 Frigates:
The first were two acquisitions of the US Navy (Type GMT or Cannon class), the Asahi and Hatsuhi. They were operational from 1855 to 1975, soon joined by the first “escorts”, the Akebono, turbine and the two diesel Ikazuchi. But it was mostly the 18 class Tacoma frigates (Kusu) transferred in 1953 and operational until 1970-73.

-50 Assault ships:
These were 49 ex-US LSSLs, which had their rocket launchers removed from fire support and were using their light support artillery (Ajisai class). They were retired for many, and all in 1961. There was also the Yorikutei type LSM, an old ship that served first under the French flag in Indochina.

-2 Submarines:
After the transfer of the USS Mingo (Gato class) in 1955, under the name of Kuroshio, Japan launched its first classic attack submarine, the Oyashio in 1959.

-66 Patrollers/minesweepers:
Classes Awaji, Reburn, Chifuri, and Yahagi, built from 1951. There were also the 12 Ukishima, dating from 1945 and partially rebuilt, and the small Yuhibari, former auxiliary SM hunters of 1945, with 26 units survivors in 1960 (about to retire after their long demining work).

-17 Minesweepers:
There were the Ukuru, 5 former 1944 high-sea patrolmen reused as tankers and minesweepers. They were scrapped in 1963-66. From 1955, the Americans delivered 9 YMS (Etajima class), 4 AMS / MSC (Yashima class) and Yashiro delivered the Yashiro in 1956, and the two Atada, larger ones. In addition, the Erimo, a wet smuggler / deep sea minesweeper was issued in 1955 and Tsugaru, a cable dragger / dredger in 1955.

-10 Sub hunters:
They were the 7 Kamomes, very inspired by the 1955-56 PC-Boats, the 1957 Great Hayabusa and the 1959 Umitaka.

-9 MTBs:
Type 1 and No. 7 and 8 (type 7) and No. 9 English origin.

-20 Coastguards:
18 patrol boats of the 18 foot type were transferred in 1955, followed by the construction of the two Muroto class coastguard patrol boats (within the ASM – Maritime Safety Agency or MSA).

The JMSDF in 1990

The reboot of Japanese industry giants was quickly followed by a massive rearmament less and less under American supervision and more through a blue water politic. Past the 2000s this move was even more compelling with a more aggressive naval policy, in particular directed against the rapid rise of the PLAN (Chinese Naval Forces). A supplementary proof of this return of strength if needs be was the launch of “helicopter destroyers” of the the Izumo and Hyuga classes. The move started by the AEGIS-capable Kongo class destroyers.

Harukaze class Destroyers
Ayanami class Destroyers
Murasame class Destroyers
Akizuki class Destroyers
Akebono/Ikazuchi class frigates
Kusu class frigates
Oyashio class Submarines
Ajisai class Landing Ships
Awaji class Patrol boats
Redburn class Patrol boats
Chifuri class patrol boats
Yahagi class patrol boats
Ukishima class Minesweepers
Yuhibari class Minesweepers
Ukuru class Minesweepers
Yashiro/Atada class Minesweepers
Type 1 class MTBs
Muroto class Coast Guards

The JMSDF in details, ship by ship

ARIAKE class DDs
Ariake and Yugure (ex. Heywood L. Edwards and Richard P. Leary) had been launched 6 October 1943 at Boston NyD, towed to Japan in 1959 to be transferred to the new fledgling navy. In 1936 both undergone reconstruction: Improved bridges, larger CiC, new radars, tripod mast. The number 3 5-in gun was discarded for weight saving. On Ariake, number 2 5-in gun was replaced by a weapon Alfa. Both ships were deleted in 1974.

ASAKAZE class DDs:
Both ships were Gleaves class destroyers, launched at Federal, Kearny (USS Ellyson) and Barth Iron Works(USS Malcomb), in 1941 and acquired 19.10.54. They were transferred under MDAP program, as the first Japanese postwar destroyers. New electronics were fitted, and the superfiring 5-in gun was discarded to make place for additional torpedo tubes. Both were returned to the USA in 1969; but then transferred agais to Taiwan.

ASHAHI class Frigates: These were ex-Cannon class (DER) escort destroyers, launched in 1943 at Federal, Newark. Transferred 14.6.1955, under MDAP and returned to the US Navy in 1975.

HARUKAZE class DDs (1955):
The first Japanese-built destroyers of the MSDF. Both were laid down at Mitsubishi Zosen, Nagasaki (Harukaze) and Shin Mistubishi HI Kobe (Yukikaze). They were designed and tailored for anti-submarine warfare. The majority of equipment was US-built, following Japan’s Mutual Defense Assistance Agreement. Sensor systems was also US standard like the AN/SPS-6 air-search radar, AN/SPS-5 surface-search radar, QHB search sonar, and QDA attack sonar.

They were armed with three 5-in/38 Mark 12 guns on Mark 30 single mounts of US manufacture, controlled by a Mark 51 director. But the JMSDF replaced the director by the Swedish-built modern GFCS developed by Contraves. On the Yukikaze, this was an American Mark 57 director. Other changes included K-guns and depth charge racks halved and later replaced by Mark 32 torpedoes. Two Mark 2 side launchers were also fitted.

Harukaze as preserved

Displacement: 1700- 2340 t FL
Dimensions 106 x 10.5 x 3.4 m
Machinery: 2 shafts Mitsubishi/Escher Weiss geared turbines or Westinghouse, 2 combustion engineering boilers or Hitachi/Babcock boilers, 30,000 bhp. 30 knots 6000 nm
Sensors: Radar SPS-5, SPS-6, Sonar SQS-29
Armament: 3x 5in/38, 8x 40 mm AA, 2 Hedgehod, DC rack, K-gun

URANAMI class DDs (1957):
This second class comprised no less than seven ships, Ayanami, Isonami, Uranami, Shikinami, Takanami, Onami and Makinami. They were laid down between 20.11.1956 and 20.3.1959, launched 1957-1960 and completed 1958-60. Builders were Mitsubishi Zosen Nagasaki, Shin-Mitsubishi on Kobe, Kawasaki from Tokyo, Mitsui Zosen from Tamano, Oshikawajima from Kobe and Ino HI from Maizuru.

They were quite different in their approach compared to the Harukaze, with a smaller artillery, more emphasis in ASW warfare, better electronics and speed. The 3-in guns were American Mk33 models, under Japanese masks. The hull was not flush deck as there was a rear step down. During these times of nuclear fear, Ayanami tested eight wahs-down systems for removing irradiated dust. ECM was also a novelty, as well as air conditioning.

VDS was mounted on three ships, their TT banks removed and replaced by Mk8 “Poor Boy” launcher. Two units at the end of their active life were converted as training ships, without their 21 in TT mount to make room for a deckhouse. Electronics were Japanese-built, although based on US designs. All has been converted as training ships, starting in 1975 up to 1985 and deleted from 1986 to 1990.

Displacement: 1720- 2500 t FL
Dimensions 109 x 10.7 x 3.7 m
Machinery: 2 shafts Mitsubishi/Escher Weiss geared turbines or Westinghouse, 2 Mitsubishi -Nagasaki CE boilers, 35,000 bhp. 32 knots 6000 nm
Sensors: Radars OPS1, 15, Sonar SQS-12/14
Armament: 3x 3in, 1x 4 21in TTs, 2 torpedo racks, 2 hedgehog, 2 y-guns

MURASAME class DDs (1958):
These three AAW destroyers which came back to a better armed solution, with new 5-in/54 guns in semi-automated Mk.39 turrets that went from the USS Midway, entirely rebuilt. However their poor rate of fire made them unsuitable as AA guns and needed large handling rooms and magazines to operate, so the hull was crowded and living conditions less than ideal.

They were also heavier than previous design, although the hull very much derived from the previous “-Nami” class. Mk 32 TTs made their apparition on two ships, Murasame and Harusame, the latter tested new systems as ASU 7006 in 1984 and latter a depot ship. All three had been built at Nagasaki (Murasame), Tokyo (Yudachi) and Yokosuka (Harusame), auxiliary in 1984 and deleted in 1984-89.


Displacement: 1838- 1840 t FL
Dimensions 110 x 11 x 3.7 m
Machinery: 2 shafts Ishikawajima geared turbines and boilers, 35,000 bhp. 32 knots, 6000 nm
Sensors: Radars OPS1, 15, Sonar SQS-29
Armament: 3x 5/54in, 3x 3in/50 AA, 2 ASW torpedo racks, 1 hedgehog, 2 y-guns, DC rack

AKIZUKI class DDs (1959):
Last units of the “old design”, the two Akizuki and Teruzuki (Nagasaki and obe, launched june 1959, completed Feb. 1960, were built under the 1954 US Military aid, and carried the same 5-in/54 guns of the Murasame.

The were however longer and much heavier to make room for the particular sub-systems of the main guns. The forecastle hull in particular was lengthened to make room for additional command facilities as they were designed as flotilla leaders. They tested the infamous ASW mortar weapon Alfa, which was a failure.

Their sensors were modernized in 1977-78, and a 375 mm Bofors ASW mortar was adopted. Six 12.75 in Mark 32 ASW TTs were also adopted. VDS was installed and a SQS-23 sonar. They became auxiliaries in 1984-85 and were deleted in 1993.


Displacement: 2380- 2890 t FL
Dimensions 118 x 12 x 4 m
Machinery: 2 shafts Mitsubishi Escher Weiss geared turbines, 4 Mitsubishi CE boilers, 45,000 bhp. 32 knots, 6000 nm
Sensors: Radars OPS-1, 15, Sonar SQS-23, OQA-1 VDS
Armament: 3x 5/54in, 3x 3in/50 AA (2×2), 1 Weapon Alfa, 2 hedgehogs, 2 y-guns, 2×4 21-in TTs, DC rack

Kusu class Patrol Ship

Isuzu class Frigates

Kurushio – Gato class Submarine USS

Work in progress…