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Umbrella state (bilateral arrangement with the United States)

Japan opted not to attend as an observer at the First Meeting of States Parties to the TPNW (1MSP) in Vienna in June 2022, generating expressions of anger and disappointment among atomic bomb survivors. The Japanese Prime Minister, Fumio Kishida, defended the decision not to participate, arguing that Japan should promote nuclear disarmament and non-proliferation in a way that allows it to maintain ‘trust with the United States, Japan’s only defence ally’.[1]

TPNW Status

TPNW Article 1(1) prohibitions: Compatibility in 2022
(a) Develop, produce, manufacture, acquire Compatible
Test Compatible
Possess or stockpile Compatible
(b) Transfer Compatible
(c) Receive transfer or control Compatible
(d) Use Compatible
Threaten to use Compatible
(e) Assist, encourage or induce Not compatible
(f) Seek or receive assistance Compatible
(g) Allow stationing, installation, deployment Compatible
TPNW voting and participation
UNGA resolution on TPNW (latest vote) Voted no (2023)
Participated in 1MSP (2022) No
1MSP delegation size (% women) N/A
Adoption of TPNW (7 July 2017) N/A
Participated in TPNW negotiations (2017) No
Negotiation mandate (A/RES/71/258) Voted no
Other weapons of mass destruction (WMD) treaties
Party to an NWFZ No
Party to the NPT Yes (Ratified 1976)
Ratified the CTBT Yes (Ratified 1997, Annex 2 state)
Party to the BWC Yes (Ratified 1982)
Party to the CWC Yes (Ratified 1995)
IAEA safeguards and fissile material
Safeguards agreement Yes (2 Dec 1977)
TPNW Art 3(2) deadline N/A
Small Quantities Protocol No
Additional Protocol Yes
Enrichment facilities/reprocessing plants Yes (Civ)
HEU stocks 1-10 tons
Plutonium stocks 46.1 tons (incl 37.t tons stored abroad)

Latest developments

Japan boycotted the TPNW negotiations in 2017 and has consistently voted against the annual UN General Assembly resolution on the Treaty, including in 2022. Japan may sign and ratify or accede to the TPNW, but will have to make changes to its policies and practices to become compliant.

At the Tenth Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) in August 2022, Japan’s Prime Minister Kishida said: ‘As a Prime Minister from Hiroshima, I believe that we must take every realistic measure towards a world without nuclear weapons step by step, however difficult the path may be.’2

In the First Committee of the UN General Assembly in October 2022, Japan submitted a draft annual resolution entitled ‘Steps to building a common roadmap towards a world without nuclear weapons’, which for the first time acknowledged the adoption, opening for signature and entry into force of the TPNW, as well as the convening of its 1MSP.3 However, Japan emphasised that it has ‘not changed its national position on the TPNW’, which it also described as ‘an important treaty that could be regarded as a final passage to a world without nuclear weapons’.4


  • Japan should renounce the possession and potential use of nuclear weapons on its behalf, and ensure that nuclear weapons do not have a role in its defence posture.

  • Japan should comply with its existing obligation under Article VI of the NPT and pursue negotiations in good faith on nuclear disarmament.

  • Japan should urgently adhere to the TPNW. Until it is in a position to do so, it should welcome the TPNW as a valuable component in the global disarmament and non-proliferation architecture, work with the Treaty's states parties on practical steps towards disarmament, and attend the meetings of states parties as an observer.

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