Japan
Japan boycotted the negotiations on the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017 and has consistently voted against the annual UN General Assembly resolutions on the Treaty, including in 2024. The government has faced mounting criticism domestically for continuing to claim reliance on the US ‘nuclear umbrella’ and refusing to engage with the TPNW. According to a survey in 2020, around three in four Japanese citizens support joining the Treaty.1 Japan may sign and ratify or accede to the TPNW, but will have to make changes to its policies and practices to become compliant.
TPNW Status
| Key weapons of mass destruction treaties | ||
|---|---|---|
| NUCLEAR WEAPONS | ||
| Party to the TPNW | No | |
| Party to the NPT | Yes (Ratified 1976) | |
| Ratified the CTBT | Yes (Ratified 1997, Annex 2 state) | |
| Party to an NWFZ | No | |
| CSA with the IAEA | Yes (In force 1977) | |
| AP with the IAEA | Yes (In force 1999) | |
| BIOLOGICAL AND CHEMICAL WEAPONS | ||
| Party to the BWC | Yes (Ratified 1982) | |
| Party to the CWC | Yes (Ratified 1995) | |
| TPNW Art. 1(1) prohibitions: Compatibility in 2024 | ||
|---|---|---|
| (a) | Develop, produce, manufacture, acquire | Compatible |
| Possess or stockpile | Compatible | |
| Test | Compatible | |
| (b) | Transfer | Compatible |
| (c) | Receive transfer or control | Compatible |
| (d) | Use | Compatible |
| Threaten to use | Compatible | |
| (e) | Assist, encourage or induce | Non-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 (2024) |
| Participated in 2MSP (2023) | No |
| Participated in 1MSP (2022) | No |
| Average MSP 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 |
| Fissile material | |
|---|---|
| Nuclear facilities | Yes |
| Fissile material production | Yes (Civilian) |
| HEU stocks | 1-10 tons |
| Plutonium stocks | 45.1 Mt (9.2 Mt in Japan) |
| SQP with the IAEA | No |
Latest developments
In December 2024, the Japanese government faced renewed domestic pressure to join the TPNW, or at least to observe its meetings of states parties, when the 2024 Nobel Peace Prize was awarded to Nihon Hidankyo, a Japanese confederation of atomic bomb survivors from Hiroshima and Nagasaki. The group said in its acceptance lecture that it was ‘overjoyed’ at the TPNW’s adoption in 2017, and has been appealing for all countries, including Japan, to sign and ratify it without delay.2
The Japanese Prime Minister, Shigeru Ishiba, said that it would be ‘extremely difficult’ for Japan to join the TPNW. ‘I do not hold the view that we should deny the extended deterrence’ provided by the US and its nuclear forces, he said.3 On the question of whether Japan would observe the Third Meeting of States Parties to the TPNW in March 2025, he was non-committal: ‘We will think about how we can play a role.’4 Komeito, the minor coalition partner in the Liberal Democratic Party-led government, has repeatedly voiced its support for observing TPNW meetings.5
In March 2024, at Japan’s initiative, the UN Security Council held a ministerial-level meeting on nuclear disarmament and non-proliferation. Addressing the meeting, the then-Minister of Foreign Affairs of Japan, Yōko Kamikawa, said that her country ‘has been a global leader in the quest to realise a world without nuclear weapons’, based on its firm belief that the ‘catastrophes of Hiroshima and Nagasaki must never be repeated’.6
She announced the establishment of a ‘global network among youth towards the elimination of nuclear weapons’ and highlighted Japan’s efforts ‘to overcome the dichotomy between deterrence and/or disarmament’, including through the funding of academic positions at foreign research institutes.
At a high-level UN event to commemorate the International Day for the Total Elimination of Nuclear Weapons on 26 September 2024, Japan said that, although the ‘pathway to a world without nuclear weapons is getting tougher’, the international community ‘must persistently pursue realistic and practical initiatives’.7
In the First Committee of the UN General Assembly in October 2024, Japan outlined its stance on the TPNW. ‘The TPNW is an important treaty that could be regarded as a final passage to a world without nuclear weapons,’ it said. ‘However, in order to change the reality, engagement with nuclear-weapon States is necessary.’8 Noting that 2025 will mark 80 years since the atomic bombings of Hiroshima and Nagasaki, Japan said that it had ‘assigned itself the mission of taking the lead in international efforts to achieve a world without nuclear weapons’.9
Recommendations
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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.
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Japan should comply with its existing obligation under Article VI of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and pursue negotiations in good faith on nuclear disarmament.
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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.