December 2022

Country Programme Japan

Japan’s Self-Defense Capability: “MinimumExtent Necessary”
On the current revision of three key documents defining the future of Japan’s
self-defense

By Naoki TAKIGUCHII．Introduction
The government and ruling parties proactively worked towards revisions of the three
key defense documents, including the National Security Strategy, and these haverecently received Cabinet approval. At the time of writing of this paper, Russian aggression against Ukraine, China's military actions, and North Korea's intermittent
missile launches have had a major impact on the general public’s awareness of national security. Given the current situation, it is reasonable to assume that the security environment around Japan will continue to deteriorate. Japan has long maintained an exclusively defense-oriented policy. Thus, in the event of an armed attack,Japan is constrained to using force to the “minimum extent necessary1” beyond proportionality.
Note: Quotes in this paper are a provisional translation of the original unless otherwise specified.

Konrad-Adenauer-Stiftung e. V.
Country ReportDecember 20222II．Policy Recommendations by the Liberal Democratic PartyIn April 2022, the Liberal Democratic Party (LDP) submitted its Recommendations
for the Formulation of New National Security Strategy, etc. (新たな国家安全保障戦略等の策定に向けた提言2) to the government. Prime Minister Fumio Kishida told theparty: “the government seriously accepts these proposals and will proceed with discussions.” The party recommendations include 1) ensuring the three defense documents are consistent with U.S. strategic documents; 2) replacing the National Defense Program Guidelines with the National Defense Strategy as a "threat-resistantdefense strategy;" 3) promoting a Free and Open Indo-Pacific (FOIP) and strengthening cooperation with allies and like-minded nations. In particular, the recommendation paper attracted significant interest both at home and abroad for its suggestionthat Japan should develop counterstrike capabilities against armed attacks on homesoil, including the increasingly possibility of ballistic missile attacks.
The proposal has one short chapter briefly explaining the "exclusively defense-oriented policy." According to media reports, LDP lawmakers were concerned that sucha defense posture would not be sufficient to counter current threats3. The proposal
mentions that the specific limitation of defense capability to the “minimum extentnecessary” will be determined in conjunction with conditions such as the prevailingsituation internationally and scientific developments. This could be interpreted assuggesting that the specific limit of force to the “minimum extent necessary” could bequite variable and elastic depending on the prevailing international situation and current progress of science and technology. Please note that the rather cumbersome
expression “minimum extent necessary” is consistent with terminology used in government documents, especially the current one.

III．What does using force to the “minimum extent necessary” actuallymean?
In December 1954, the year before the integration of conservative forces (namelythe then Liberal Party and Democratic Party) in Japan, the then-government, uponrequest of the National Diet, issued an official position on the interpretation of Article
9 of the Constitution. This document stated "it is no violation of the Constitution forJapan to have a self-defense body, such as the Self Defense Forces, and to establish
a competent force to necessary extent for that purpose." This reinterpretation wouldcause anything exceeding the “minimum extent necessary” as “war potential4”.
Yasuaki Chijiwa, Senior Fellow of the National Institute for Defense Studies, explains5:
1) The predecessors of the Self-Defense Forces (SDF) did not have "modern warfare
capabilities," therefore, they did not fall under the “war potential” prohibited by theConstitution and thus were not considered unconstitutional,
2) Later on, regardless of whether or not Japan possessed modern warfare capabilities, the Constitution was reinterpreted to accept the organization of forces as constitutional, provided that use is no more than to the “minimum extent necessary."
The latest government position voiced in the National Diet reads as follows: "thespecific limit is subject to change according to the prevailing international situation,
the level of military technologies, and various other factors, and it is discussed and22

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decided through annual budget and other deliberations by the Diet on behalf of thepeople.6" Thus, we are unable to make generalisations about the specific limit. However, offensive weapons designed only to cause mass destruction in another country
are not permissible under any circumstances as their use would directly exceed thedefinition of the “minimum extent necessary” for self-defense. For example, the SDF
is not allowed to possess intercontinental ballistic missiles (ICBM), long-range strategic bombers, or attack aircraft carriers. The reference to the "prevailing international situation and the level of military technologies" was first made by Masaharu
Kondo, Commissioner of the Cabinet Legislation Bureau, at a session of the Committee on Security of the House of Representatives on July 8, 2020. Since 1954,
successive governments have frequently used the expression “minimum extent necessary” to respond to questions in the Diet. Prior to July 2020, however, the government position was generally that "the specific limit to the use of force, which is to the“minimum extent necessary”, is in accordance with the scale and manner of thearmed attack in question, and it is difficult to state these in general terms."

IV. Concept Remains Untouched
Meanwhile, Prime Minister Kishida has reiterated7 that the government will maintainits exclusively defense-oriented policy. Itsunori Onodera, Chairperson of the LDP
Research Commission on Security, who was responsible for formulating the abovementioned proposal, commented, "if the ‘minimum extent necessary’ is to bechanged, the interpretation of the Constitution and all previous government responses in the Diet must also be changed. Time-consuming efforts that could takeas long as developing the 2015 Security Legislation or even longer would have to bemade. In today’s tough security environment, we tried to do what we could and leftthe ‘minimum extent necessary’ unchanged8." He made it clear that the while theconcept had been a subject of debate, the party has chosen to maintain the “minimum extent necessary”. This is a judgement based on maintaining consistency withprevious interpretations of the Constitution.
During revision of the three defense documents, the government and ruling parties
decided to specifically mention that Japan would possess counterstrike capabilities
to the “minimum extent necessary9”, and the LDP and Komeito agreed on executing
counterstrike capabilities provided this meets the three new requirements for exercising the right to self-defense. Komeito has historically been cautious about allowing
Japan to possess counterstrike capabilities, but the party position has shifted towards tolerating its possession. However, the junior coalition partner still believes
that the government should refrain from carrying out counterstrikes as a preemptiveaction The use of preemptive strikes will remain impermissible. Counterstrikes canalso be utilised in the case of an armed attack on a Japanese ally.
In May 2020, at a meeting of the House of Representatives Commission on the Constitution, Yuichiro Tamaki, President of the Democratic Party for the People, asked
the LDP for its views on the concept of the “minimum extent necessary”. Yoshitaka
Shindo, the ruling party’s Senior Director for the Commission and deputy chief of theLDP Policy Research Council stated10 that: 1) the concept had previously been classified as a quantitative one. 2) the major premise is that it is subject to change inaccordance with relative security and the content of threats to Japan. 3) it would
require a quantitative, relative, and comprehensive judgement going forward. Therefore, the party’s current position concept is that the “minimum extent necessary” is
not only quantitative, but also relative, and comprehensive.

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4V. Conclusions
Although the three defense documents are a turning point, security policies remain
constrained by the Constitution. Counterstrike capabilities are one of the main focal
points. However, the legal foundation for these had already been established as of1956. This time, the government has made a policy shift to retain capabilities andrelated assets at hand. This broadens the scope and capacity of Japan’s security
policy. Meanwhile, Shigenobu Tamura, a former advisor to the LDP Policy ResearchCouncil, says even after the revision of the three defense documents, "the foundations (of security policy) will not change11." With this clear relativization, the conceptof the “minimum extent necessary” can change depending on the prevailing international situation and scientific and technological advances. In addition, the government can alter the scope of assets possessed by the SDF. These circumstances will
have an impact on Japan’s entire security policy, including the shape of the U.S.Japan alliance. I believe that such potential shifts in the direction of national security
strategy are in fact more significant than the possession of counterstrike capabilities.
The government has been taking every opportunity to reiterate its intention to "fundamentally reinforce Japan’s defense capabilities". It has already announced that it
will aim to increase the defense budget by at least 2% within five years. As a result,
PM Kishida ordered both the Finance and Defense Ministers to implement this increase by FY2027, and the LDP had very active discussions over the issue.
While Japan has made clear progress on the revised defense budget, counterstrikecapabilities, and the assets of defense equipment, certain limitations will remain inplace. As Akihisa Nagashima, a member of the House of Representatives wellversed in defense issues, points out, the elasticity of the concept of the “minimumextent necessary” could undermine constitutional norms and goes against constitutionalism. He calls for constitutional amendments in order to respond to national security realities12. From the known facts, it can be concluded that in due course there
will be productive debates to strengthen constitutionalism and Japan’s security policy.

Note: Not all references are available in English.
1 The “minimum extent necessary” 必要最小限度 in this article refer to the use of force and as-sets of the Self-Defense Forces.
2 Liberal Democratic Party (April 25, 2022) Recommendations for the Formulation of New Na-tional Security Strategy, etc. 新たな国家安全保障戦略等の策定に向けた提言
https://www.jimin.jp/news/policy/203401.html
3 Sankei Shimbun (April 12, 2022) Exclusively defense-oriented policy: LDP rethinks correspond-ing to the change in security environment 専守防衛

自民見直し論 安保環境の変化に対応

4 Constitution of Japan (May 3, 1947) Article 9
5 Yasuaki Chijiwa（May 25, 2022）Chuko-Shinsho Japan’s Postwar Security 戦後日本の安全保障
6 Ministry of Defense, White Paper 2022 https://www.mod.go.jp/en/publ/w_pa-

per/wp2022/DOJ2022_EN_Full_02.pdf
7 House of Representatives Plenary (May 25, 2022） Prime Minister Fumio Kishida https://kok-kai.ndl.go.jp/txt/120805254X02920220525/25

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58 Nikkei Shimbun（June 9, 2022）“Counterstrike Capabilities“ to open the Pandora’s box パンド

ラの箱開ける「反撃能力」 自衛権の限界論争再び https://www.nikkei.com/article/DGXZQOCD018QR0R00C22A6000000/
9 National Security Strategy (Provisional Translation) December 2022 (December 16, 2022) Cab-

inet Secretariat https://www.cas.go.jp/jp/siryou/221216anzenhoshou/nss-e.pdf
National Defense Strategy (Provisional Translation) December 2022 (December 16, 2022) Ministry of Defense https://www.mod.go.jp/j/approach/agenda/guideline/strategy/pdf/strategy_en.pdf
Note: In these document, the “minimum extent necessary” is referred as “minimum necessary.”
10 House of Representatives Commission on the Constitution（May 19, 2022）Member of theHouse of Representatives Yoshitaka Shindo https://kokkai.ndl.go.jp/txt/120804183X01320220519/16
11 Shigenobu Tamura Former Advisor to the LDP Policy Research Council, Adjunct Fellow to theJapan Institute of International Affairs（November 22, 2022）Interview at a Tokyo venue
12 Akihisa Nagashima Member of the House of Representatives（May 19, 2022）

https://twit-ter.com/nagashima21/status/1527127802977611776（All the links last accessed December 16, 2022）（References）Following references are all Japanese publications


Shigenobu Tamura (October 1, 2018, Naigai Publishing, New Defense Legislation 新・防衛法制Legislative Bureau, Cabinet Office （January 30, 2017）Government’s responses related tothe Constitution (Article 9 / Constitutional interpretation) 憲法関係答弁集（第 9 条・憲法解釈関係）
Kazumasa Imai （March 15, 2022）"Weapons the Self-Defense Forces Can Possess: The
Limit to the “Minimum Extent Necessary” of Self-Defense Force"「自衛隊の保有しうる兵器―必要最小限度の自衛力の限界―」

Tokyo Kansho Fukyu Toki no Hourei

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6The AuthorNaoki Takiguchi is the Senior Programme Manager / Political Analyst for Country
Programme Japan of the Konrad-Adenauer-Stiftung (KAS). Prior to joining KAS, heserved as a Policy Advisor to Diet Member Akihisa Nagashima and functioned invarious positions at the Embassy of Sweden Tokyo, and the Democratic Party ofJapan (DPJ). Takiguchi served concurrently as a Special Researcher at the Cabinet
Secretariat under the DPJ government. Takiguchi won the Secretary-General Awardof the Liberal Democratic Party International Bureau’s 2022 International Politics andDiplomatic Dissertation Contest. Takiguchi holds the license of Aide for Policy andLegislative Affairs to Diet Members.

Konrad-Adenauer-Stiftung e. V.
Naoki Takiguchi
Senior Programme Manager / Political Analyst
Country Programme Japan
www.kas.de/japan
naoki.takiguchi@kas.deDecember 19, 2022

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