## Facts

- In August 1945, the United States dropped atomic bombs on Hiroshima (Aug. 6) and Nagasaki (Aug. 9), causing extensive civilian deaths, injuries (including long-term radiation harm), and property destruction.
- Five Japanese plaintiffs, including survivors and relatives of victims, sued the State of Japan in 1955 for civil damages arising from those injuries and losses.
- Plaintiffs asserted the bombings violated international laws of war, including prohibitions on indiscriminate bombardment and on means of warfare causing unnecessary suffering.
- Plaintiffs alleged Japan later waived “all claims of Japan and its nationals” against Allied powers in Article 19(a) of the 1951 San Francisco Peace Treaty, thereby sacrificing their potential claims and creating a domestic duty for Japan to indemnify them.
- Japan argued no applicable positive international law in 1945 specifically prohibited atomic bombs and denied that the treaty waiver created domestic compensation liability.
- The Tokyo District Court issued a first-instance judgment on December 7, 1963, dismissing the claim; no appeal was taken.

## Issues

1. Whether the atomic bombings of Hiroshima and Nagasaki were unlawful under the international law governing the conduct of hostilities in 1945.
2. Whether individual victims possessed an independent international-law right to claim reparation, and whether Japan’s peace-treaty waiver wrongfully extinguished any such rights.
3. Whether domestic law permitted damages against Japan based on the alleged illegality of the bombings and Japan’s treaty-based waiver of claims.

## Decision

- The court held the atomic bombings of Hiroshima and Nagasaki were illegal acts of hostilities under then-applicable international law.
- The court held individual victims lacked a direct right to seek damages on the plane of international law for those violations.
- The court concluded Japan could validly waive war-related claims, including claims asserted via diplomatic protection, under Article 19(a) of the San Francisco Peace Treaty.
- The court held the plaintiffs had no enforceable rights against the United States that were taken by the waiver and therefore could not base damages on the waiver itself.
- The court determined municipal law did not provide a viable path to damages against Japan for treaty-making and war-settlement acts; the action was dismissed.

## Legal Principles

- The legality of a weapon or attack is assessed under general laws-of-war limits (including distinction and the ban on indiscriminate bombardment), not solely by the presence or absence of an express treaty prohibition.
- Customary rules prohibiting indiscriminate bombardment of undefended cities, and protecting civilian populations through the distinction between military and non-military objectives, applied to aerial bombardment in 1945.
- Use of means of warfare producing severe, widespread, and indiscriminate effects on civilians may violate the prohibition on unnecessary suffering and related limits on methods of warfare.
- Under a state-centric approach to international law, reparation claims for wartime injury to nationals generally belong to the state and are ordinarily pursued through diplomatic protection unless a treaty grants individuals a direct right of action.
- A state may waive international claims arising from war, including claims tied to nationals, through a peace treaty; absent an individual right recognized by international law, individuals cannot claim deprivation of rights based on the waiver.
- Domestic damages claims may be barred where the challenged conduct is sovereign in character (e.g., foreign relations and peace settlement) and not subject to ordinary civil liability.

## Conclusion

The court treated the Hiroshima and Nagasaki atomic bombings as unlawful under customary laws of war, but denied compensation because international law did not grant individuals a direct reparations claim and Japan’s peace-treaty waiver validly foreclosed state-level claims without creating domestic liability to indemnify the plaintiffs.


Shimoda v. State, 355 Hanrei Jiho 17 (Tokyo Dist. Ct. 1963)