Overview
The Russia–Japan territorial dispute concerns four islands at the southern end of the Kuril chain, administered by Russia but claimed by Japan.
They are:
- Iturup / Etorofu
- Kunashir / Kunashiri
- Shikotan
- Habomai islets
Japan collectively calls them the Northern Territories. Russia treats them as part of the Southern Kurils.
The unresolved dispute has prevented Russia and Japan from concluding a formal post-World War II peace treaty.
Historical Background
Treaty of Shimoda, 1855
The first formal Russo-Japanese boundary was established between:
- Etorofu, on the Japanese side; and
- Urup/Uruppu, on the Russian side.
Japan therefore cites the 1855 settlement as an important historical basis for its claim to the four southern islands.
Treaty of St. Petersburg, 1875
Japan gave up its claims over Sakhalin in exchange for Russia transferring the remaining Kuril Islands to Japan.
World War II and Soviet Occupation
In August 1945, the Soviet Union entered the war against Japan and subsequently occupied the southern islands.
The Soviet Union incorporated them into its territory, and the Russian Federation retained control after 1991.
Japan disputes the legality of this outcome and argues that the four Northern Territories were distinct from the Kuril Islands it renounced after World War II. Russia maintains that sovereignty over the islands was settled by the outcome of the war.
Competing Claims
Japan’s Position
Japan maintains that all four islands are an inherent part of Japanese territory.
Its stated objective is to resolve their attribution and conclude a peace treaty with Russia.
Japan distinguishes the four islands from the broader Kuril chain.
Russia’s Position
Russia exercises effective administration and considers sovereignty over the islands legally established by the outcome of World War II.
It rejects Japan’s characterisation of Russian control as illegal and has increasingly treated the sovereignty question as settled.
1956 Soviet–Japanese Joint Declaration
The 1956 Joint Declaration restored diplomatic relations between Japan and the Soviet Union.
It provided that, following conclusion of a peace treaty, the Soviet Union would hand over:
- Shikotan
- Habomai
to Japan.
It did not provide for the transfer of Kunashir or Iturup.
This created the basis for a possible “two-island solution”, but no peace treaty was concluded and the transfer never occurred. Japan continues to regard the 1956 Declaration as legally valid.
Why the Islands Matter
The dispute is not merely historical.
Strategic Importance
The island chain lies between the Sea of Okhotsk and the Pacific Ocean.
For Russia, control helps secure:
- access routes for the Pacific Fleet;
- approaches to the Sea of Okhotsk;
- operating areas used by strategic ballistic-missile submarines.
Iturup and Kunashir are therefore particularly important from a military perspective.
Economic Importance
The surrounding waters contain valuable:
- fisheries;
- marine resources.
The wider Kuril region also has geothermal and mineral potential.
Maritime Significance
Control of the islands affects jurisdiction over surrounding:
- territorial waters;
- fishing grounds;
- maritime zones.
Why No Peace Treaty Exists
Japan and the Soviet Union restored diplomatic relations in 1956, but they never signed a formal peace treaty ending the World War II settlement.
The principal obstacle has been disagreement over the territorial status of the four islands.
Various negotiations followed, including:
- the 1956 Joint Declaration;
- the 1993 Tokyo Declaration;
- renewed negotiations during later Japanese and Russian governments.
None produced a final settlement.
Impact of the Ukraine War
Relations deteriorated sharply after Japan imposed sanctions on Russia following Russia’s 2022 invasion of Ukraine.
Russia subsequently suspended peace-treaty negotiations and related dialogue mechanisms.
This effectively froze an already difficult negotiating process and reduced prospects for an early territorial compromise.
Latest Development: 2026
The dispute again intensified in August 2026 when Russian President Vladimir Putin visited Iturup/Etorofu, his first visit to the disputed island chain.
Japan strongly protested the visit, describing it as incompatible with its territorial position, while Russia reiterated that the islands are Russian sovereign territory.
On 18 August 2026, Russia formally protested to Japan’s ambassador over Japanese Prime Minister Sanae Takaichi’s statements concerning the islands, demonstrating that the territorial issue remains an active source of bilateral tension.
Four Islands: Strategic Distinction
| Territory | Russian name | Japanese name | Relative significance |
| Iturup | Iturup | Etorofu | Largest; major strategic importance |
| Kunashir | Kunashir | Kunashiri | Close to Hokkaido; strategic and fisheries importance |
| Shikotan | Shikotan | Shikotan | Included in proposed 1956 transfer |
| Habomai | Habomai | Habomai | Small islets closest to Hokkaido; included in proposed 1956 transfer |
Wider Geopolitical Significance
The dispute intersects with broader Northeast Asian geopolitics involving:
- Russia’s Pacific military posture;
- Japan–US security relations;
- Russian concerns over US military presence in Japan;
- China–Russia strategic alignment;
- maritime security in the North Pacific.
This explains why even apparently small islands have strategic importance disproportionate to their land area.
Conclusion
The Russia–Japan territorial dispute is an unresolved consequence of the World War II settlement involving Iturup/Etorofu, Kunashir/Kunashiri, Shikotan and Habomai. Russia exercises effective control, while Japan claims sovereignty over all four. The 1956 Joint Declaration provides a historical basis for possible transfer of Shikotan and Habomai, but deteriorating relations since 2022 and renewed tensions in 2026 have made a near-term settlement increasingly unlikely.
