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There are different claims ofwars extended by diplomatic irregularity which involve long peaceful periods after the end of hostilities where, for various reasons, the belligerents could be considered to be in a technical state of war. For example, occasionally small countries named in adeclaration of war would accidentally be omitted from apeace treaty ending the wider conflict.

Such "extended wars" are discovered much after the fact, and have no impact during the long period (often hundreds of years) after the actual fighting ended. The discovery of an "extended war" is sometimes an opportunity for a friendly ceremonial peace to be contracted by the belligerent parties. Such peace ceremonies are even conducted after ancient wars where no peace treaty was expected in the first place, and in cases where the countries were not even at war at all. These "treaties" often involve non-sovereign sub-national entities, such as cities, who do not in reality have the power to declare or end wars.

Related situations (not necessarily listed below) include:

• Frozen conflicts, where anarmistice (ceasefire) is signed or fighting comes to an end, but there is intentionally nopeace treaty because the underlying political conflict has not been resolved.
• A state of war that ends without a peace treaty when the original declaration of war was deemed to be illegal, such as the declaration of war byThailand against theUnited States was mutually recognized to be afterWorld War II.
• Political conflicts that continue after the signing of a peace treaty that formally ends the state of war. For example, theSoviet–Japanese Joint Declaration of 1956 ended the state of war between Japan and the Soviet Union that was declared during World War II, but theKuril Islands dispute remains an unresolved consequence of the war.

Combatants	Historical conflict	Period ofde facto conflict[i]	De jure peace	De facto duration, years	De jure duration, years	De facto –de jure difference, years	Status of claim
Isles of Scilly vs Dutch Republic	First Anglo-Dutch War (Three Hundred and Thirty Five Years' War)	1651–1654	1986	4	335	329	TheDutch Republic underMaarten Tromp declared war solely on theIsles of Scilly, as the final stronghold of the Royalist naval force which was capturing Dutch merchant ships. When the Dutch and theCommonwealth of England signed theTreaty of Westminster (1654), this separate state of war was not mentioned and thus not included in the peace. The Dutch ambassador, visiting in April 1986 to conclude peace, joked that it must have been harrowing to the Scillonians "to know we could have attacked at any moment."[1]
Huéscar vs Denmark	Peninsular War	1809–1814	1981	6	172	167	TheSpanish town ofHuéscar declared war onDenmark, as a result of theNapoleonic wars over Spain, where Denmark supported theFrench Empire. The official declaration of war was forgotten until it was discovered by a local historian in 1981, followed by the signing of a peace treaty on 11 November 1981 by the city mayor and the Ambassador of Denmark. Not a single shot was fired during the 172 years of war, and nobody was killed or injured.[2][3][4]
Montenegro vs Japan	Russo-Japanese War	1904–1905	2006	2	102	101	Montenegro declared war in support of Russia but Montenegro lacked a navy or any other means to engage Japan. After Montenegro (independent in 1904, but united withSerbia by 1918) had voted in 2006 to resume its independence, it concluded a separate peace treaty in order to establish diplomatic relations with Japan.[5][6] SeeJapan–Montenegro relations.
Costa Rica vs Germany	World War I	1918	1945	1	28	27	Due to a dispute over the legitimacy of the government ofFederico Tinoco Granados,Costa Rica was not a party to theTreaty of Versailles and did not unilaterally end the state of war.[7] The technical state of war ended after World War II only after they were included in thePotsdam Agreement. Costa Rica did not issue a declaration of war against Germany in World War II.[8]
Soviet Union vs Japan	Soviet–Japanese War (Part ofWorld War II)	1945	1956	1	11	10	TheSoviet–Japanese War was a short conflict that lasted less than a month in 1945. However, despite this, the Soviets refused to sign theTreaty of San Francisco and did not unilaterally end the state of war. Ultimately, the state of war was not formally ended until theSoviet–Japanese Joint Declaration of 1956,[9] 11 years later.
Poland vs Japan	World War II	1941–1945	1957	4	16	12	In December 1941, thePolish government-in-exile unilaterally declared war on Japan. However, as Soviet-occupied Poland refused to sign theTreaty of San Francisco, the country also did not unilaterally end the state of war. Ultimately, the state of war was not formally ended until 1957, when Japan concluded a separate peace treaty in order to establish diplomatic relations with thePolish People's Republic.[a][10][11] SeeJapan–Poland relations.
UN Forces (led by United States) vs Iraq	Gulf War	1991	2003	1	13	12	TheUNresolution which ended the first Gulf War only enacted a ceasefire. It did not end the state of war with Iraq.[12] TheBritish Government would, 12 years later, use thede jure state of war with Iraq to provide the legal basis for the2003 invasion of Iraq.[13]Opponents of the Iraq War have criticised this interpretation, with one source labelling it as "legal gymnastics" (seeLegality of the Iraq War).[14][15][16]
^Period between declaration of war andde facto peace

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