Caption: Landing party on Eminiar VII
M-class planet with an advanced civilization that has been at war with its neighboring planet, Vendikar, for over 500 years.
While on a diplomatic mission, the crew of the U.S.S Enterprise discovered that the two planets learned to avoid the complete devastation of war by using computers to simulate the outcomes of a real attack. When a "hit" was scored by one of the planets, the people declared "dead" willingly walked into antimatter chambers and were vaporized.
Captain Kirk and Spock eventually destroyed the computers. Kirk told the Eminiar VII council members that they made this war too easy for themselves and that they will truly experience the horrors of war if they do not learn to make peace first.