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Japan Maritime Self Defence Force Plans

In 1969 President Richard Nixon coaxed a reluctant Prime Minister Eisaku Sato to agree publicly that the security of Taiwan was “important” to Japan –in exchange for the return of occupied Okinawa to Japanese sovereignty. Sato subsequently pocketed Okinawa and ensured that no Japanese commitment was made to help the United States defend Taiwan.

In the 1980s under the U.S.-Japan “Roles and Missions” construct and the Reagan administration’s Maritime Strategy, the government of Yasuhiro Nakasone took responsibility for building up its military capabilities to defend straits north of Hokkaido and bottle-up the Soviet Fleet in the Sea of Okhotsk so that US Air and Naval forces could destroy them.

The Maritime Self-Defense Force (MSDF) had an authorized strength in 1992 of 46,000 and maintained some 44,400 personnel and operated 155 major combatants, including thirteen submarines, sixty-four destroyers and frigates, forty-three mine warfare ships and boats, eleven patrol craft, and six amphibious ships. It also flew some 205 fixed-wing aircraft and 134 helicopters. Most of these aircraft were used in antisubmarine and mine warfare operations. The MSDF's former unit structure emphasized anti-submarine and mine warfare.

In the 1997 version of the U.S.-Japan Defense Guidelines, which were promulgated in part because of China’s saber rattling against Taiwan, Japan agreed for the first time to plan for cooperation with U.S. forces in “situations in the area surrounding Japan that have a direct impact on Japan’s security.” Since around 2010, Japan has been shifting its Northern-focused Cold War posture towards the South to use its archipelagic advantage to respond to China’s expansion.

1995 National Defense Program Outline

The National Defense Program Outline which determines Japan's defense capabilities, was reviewed and newly established in December 1995. The MSDF's former unit structure emphasized anti-submarine and mine warfare. After reorganization, the MSDF will become a more functionally balanced force capable of conducting a variety of operations ranging from surveillance and patrol in surrounding sea areas to such public welfare support as disaster relief activities.

In order to ensure the safety of Japan's maritime transportation when an emergency such as aggression at sea takes place, the MSDF must constantly keep at least one escort flotilla as a mobile operating ship unit so that it can be dispatched to sea areas where armed attacks take place. However, four escort flotillas would be needed in order to constantly keep at least one escort flotilla on a rapid response posture. This is because a considerable period of time is needed for basic training of personnel following relief of crew members of ships, as well as for repair of ships, and the period of time for an escort flotilla to maintain a high level of proficiency in performing duties under difficult conditions is limited. Consequently, the MSDF will maintain four escort flotillas. "Anti-submarine surface ship units" mentioned in the previous Outline were renamed "destroyer units" in the new Outline, because all patrol chasers (PC) exclusively engaged in mission of anti-submarine warfare were removed from service.

The previous Outline divided Japan's sea areas into five districts (defense districts) in conformity with the nation's geographic characteristics, for the purpose of coastal surveillance and defense. Two destroyer divisions were assigned to each regional defense district for surveillance and defense so that at least one destroyer division was always on a combat ready basis. Accordingly, the MSDF possessed a total of 10 destroyer divisions. Under the new structure of the MSDF, from the viewpoint that the MSDF must ensure such a posture at least to leave no room for deficiencies in the regions, it will possess seven destroyer divisions in order to be ready to deploy one each destroyer division in the five defense districts, as well as in the Tsugaru and Tsushima straits. Accordingly, the number of destroyers assigned to destroyer units (for mobile operations and regional districts units) would be reduced to about 50 compared with about 60 under the previous Outline.

Submarine units engage in surveillance and defense in major straits. In order to ensure the safety of Japan's maritime transportation, the MSDF needs to maintain the posture capable of deploying two submarines each in the three straits of Soya, Tsugaru and Tsushima, where necessary. In order to maintain such capability, it would be necessary to possess six divisions with 16 submarines, taking into account geographical relations between submarine bases and sea areas where submarines engage in surveillance and defense. The MSDF would maintain six divisions with 16 submarines.

Under the previous Outline, minesweeping units, as ship units which engage in, as necessary, removal and disposal of mines laid in main harbors and straits, were maintained with two minesweeping flotillas one each assigned to the East Japan and West Japan Sea areas, in conformity with Japan's geographical characteristics. Under the 1995 Outline structure of the MSDF, the two flotillas would be unified into one from the viewpoint of maintaining minimum functions.

Under the 1995 Outline, the number of land-based patrol aircraft units was set at 13 squadrons, compared with 16 set in the previous Outline. Broken down into details, 1) fixed-wing patrol aircraft units engaging in surveillance in nearby seas will be reduced to eight squadrons from 10, and 2) land-based patrol helicopter units engaging in surveillance and defense in main harbors and straits would be reduced to five squadrons from six. Aircraft previously called "anti-submarine aircraft" were referred to as "patrol aircraft" in the Outline because anti-submarine aircraft would engage in extensive surveillance patrols over the sea, not limited to anti-submarine missions.

As to fixed-wing patrol aircraft units, the MSDF previously possessed eight squadrons with 80 aircraft needed to conduct patrols at least once a day in Japan's nearby seas where necessary, and two squadrons with 20 aircraft capable of escorting ships. Under the new MSDF structure, the two squadrons with 20 aircraft engaging in the latter mission would be abolished because assignment of patrol aircraft for the escort of ships would no longer be considered from the viewpoint of defense buildup.

As to land-based patrol helicopter units, the MSDF previously possessed six squadrons, one each assigned to the two straits of Tsugaru and Tsushima, as well as four regions of Keihan, Hanshin, Japan Sea and Okinawa, to provide defense for straits and harbors. Under the new structure, MSDF would possess five squadrons, one each to five defense districts, from the viewpoint of ensuring the minimum posture and not creating a lack of regional capability.

Due to the MSDF structural changes, the number of combat aircraft was to be reduced to about 170 from about 220 possessed under the previous Outline.

2004 Mid-Term Defense Program (JFY 2005-2009)

The National Defense Program Guidelines in and after JFY 2005 and Mid-Term Defense Program (JFY 2005-2009) were adopted by the Security Council and the Cabinet on 10 December 2004. The latest changes to MSDF organisation was elaborated in the December 2004 guiding documents, the National Defence Program Outline (NDPO) and the Mid-Term Defence Program (MDP). The MSDF is to be reorganised by planned moves to consolidate the number of escort divisions of the destroyer units for mobile operations into eight, each of which is deployed four destroyers; and abolish one of Escort divisions for regional deployment. Additionally, there is a plan to consolidate the number of divisions of the submarine unit into five, flight squadrons of fixed-wings patrol aircraft unit into four and patrol helicopter unit into five.

The 19DD program is linked to a restructure outlined in the JDA's core policy document, the National Defence Program Guideline. This would see the number of Maritime Self-Defence Force (MSDF) escort divisions reduced to eight from the previous 12, with the number of ships in each increased to four from two to three. The plan envisaged four flotillas, each composed of two types of escort divisions: four DDH groups, consisting of one of the future helicopter carrier destroyers, one Kongo-class destroyer and two other destroyers; and four DDG groups, comprising one Kongo and three other destroyers. Thus a total of thirty two destroyers of various types are required, including eight Kongo class destroyers. A 19DD will be deployed with each group to provide protection against surface, sub-surface and air threats, to allow the Kongo to focus on missile defense. Exact classes making up the two types of escort division had yet to be released as of 2008. However, the two types of escort division are geared to become the main tactical units of the MSDF surface-combat fleet, providing the navy with more operational flexibility. Parallel to this change, the MSDF planned to reduce the number of its district-level escort divisions to five from the current seven.

The number of major surface combatants would drop from 52 to 47 during the FY05-09 Mid-Term Defense Plan. Exactly how this is to be achieved was not immediately clear, but one plausible scenario would focus on retiring the least capable and oldest vessels assigned to the district-level escort divisions. This would encompass retiring the single unit of the DE-226 Ishikari class, the two units of the DE-227 Yubari class, and three units of the DE-229 Abukuma.

2022 National Defense Strategy

In accordance with the “National Defense Strategy” (approved by the National Security Council and Cabinet on December, 16, 2022), MSDF will decommission vessels that have been in service for a considerable amount of years and have limitations in expandability, etc., and increase the number of labor-saving frigate (FFM), etc., at an early date. In addition, in order to enable diverse operations such as distributed maneuver operations, MSDF will increase the number of air defense destroyers and improve the air defense and electronic warfare capabilities of destroyers and frigates (DDG, DD, and FFM). Furthermore, to enhance mine warfare capabilities, the number of minesweepers that control unmanned minesweeping assets will be increased, and the number of replenishment ships will be increased to strengthen logistical support capabilities on the sea. In addition, in order to respond to air attacks in a contingency, etc., the modification of destroyers ("Izumo" type) will be promoted to enable the operation of fighter aircraft (F-35B). MSDF will procure fixed-wing patrol aircraft (P-1) with enhanced capability and patrol helicopter (SH-60K (upgraded version)), and improve the electronic warfare, anti-ship attack, and other capabilities of fixed-wing patrol aircraft.

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Page last modified: 28-03-2023 13:43:03 ZULU