This is when either a person or a group (oftentimes a country) initiates a conflict on another without any provocation. While most wars are started because tensions between these two groups worsens, or because one group wants the other's land, food, women, etc., this is when the two groups appear to be on good terms and in general peacetime, when suddenly one of them attacks the other for no reason and initiates war.
- Such an attack is the climax of the first Safehold book, Off Armageddon Reef, in which the Group of Four, leaders of the Church of God Awaiting decide to force the major naval powers of the world to wipe out Charis out of fear of their innovative natures.
- The Battlestar Galactica reimagining started with the Cylons launching a surprise nuclear attack on all 12 Colony worlds after decades of peace, annihilating most of the human population.
- Starfire scenario "The Paurl Harbor Raid". The Rigellians started their war with the Khanate of Orion by sending their carriers to destroy Khanate battleships "at anchor" in Paurl Harbor (a Shout-Out to the Japanese attack on Pearl Harbor).
- Some German invasions of countries during World War II, starting with Poland, September 1st 1939 (followed by Denmark, Norway, the Netherlands, etc.)
- The Japanese attack on Pearl Harbor, December 7th 1941.
- The Iraqi invasion of Kuwait, August 2nd 1990.
- In Ace Combat 5: The Unsung War, Yuktobania declaring war on Osea and attacking in force within hours after that is presented as such. However, it is later revealed that both sides have been covertly provoked by a third party until one of them snapped and retaliated, believing that the other "knew what they did".
- In Xenoblade, it's eventually revealed that Zanza attacked the Mechonis without provocation while the people of Mechonis and Bionis were previously at peace.