A Cardassian star system captured in the Federation alliance's first major offensive of the Dominion War and later lost again.
Chin'toka is a star system in Cardassian territory. In Tears of the Prophets, Starfleet launches its first great offensive of the Dominion War against Chin'toka, racing to strike before automated orbital weapons platforms come online. The fleet takes heavy losses until the Defiant destroys the platforms' power source, and the system is captured.
The allies hold it for months, but in The Changing Face of Evil the Dominion and its new Breen allies retake Chin'toka in a crushing defeat in which the Defiant is destroyed.