List of wars extended by diplomatic irregularity

There are different claims of wars extended by diplomatic irregularity, sometimes by a small country named in a declaration of war being accidentally omitted from a peace treaty concerning the wider conflict. These "extended wars" have only been discovered 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 ceremonial peace to be contracted by the belligerent parties. This can boost tourism and the relations between states involved by providing interaction not before engaged in, and in some cases, starting relations that have not occurred for historical or geographic reasons. Ceremonial peace, in these cases, is often good natured and for this reason can involve the highest levels of government or foreign affairs offices.

Such a situation is to be distinguished from that of parties deliberately avoiding a peace treaty when political disputes outlive military conflict, as in the Kuril Islands dispute between Japan and Russia.