The Chin'toka system was a Cardassian planetary system located near the Federation border. This system contained four planets, two of them inhabited. It was the scene of two major confrontations in the Dominion War. This system was located in the Alpha Quadrant.
At the end of 2374, the system was protected by only five squadrons of Jem'Hadar attack ships because the rest had been diverted to reinforce Dominion forces along the Romulan front. This vulnerability provided an opportunity for Allied forces to launch an invasion of Cardassian space. However, the Cardassians had anticipated their attack and deployed hundreds of orbital weapon platforms in the system. These platforms nearly turned the battle against the Allied forces, until a way was found to neutralize them. Subsequently, the system fell to Allied forces. (see First Battle of Chin'toka) (DS9: "Tears of the Prophets")
However, the invasion did not proceed further than Chin'toka as was hoped; the victorious Allies remained bottled up in the system, fending off constant Dominion attacks. (DS9: "Image in the Sand", "The Siege of AR-558")
The Chin'toka system remained under Allied control for most of 2375, until it was retaken by a combined force of Dominion and Breen warships. An Allied attempt to repel their advance ended disastrously, in which 311 of 312 ships were destroyed with relative ease. This was due to Allied unpreparedness for the Breen energy dampening weapon, which rapidly disabled the fleet, leaving all affected ships completely defenseless (see Second Battle of Chin'toka). (DS9: "The Changing Face of Evil", "When It Rains...")
- Chin'toka (primary)
A close-up shot of a tactical map in the beginning of "When It Rains..." shows the position of Chin'toka in relation to Ferenginar, Starbase 375, Cardassia, Bajor and the Badlands. Chin'toka was labeled by one of its planets, AR-558, in the map.
An infographic depicting the Chin'toka system in DS9: "Tears of the Prophets" reads: "Chin'toka; Cardassia; binary orbit; perihelion 107 km; aphelion 109 km." The perhelion was a body's point of smallest, the aphelion that of greatest distance from its orbital center. It is not known if these parameters are referring to the binary M-class planets seen in the episode, as this would mean, that the described orbital distance varies by a factor of 100. (Earth's mean distance from the sun is ca. 1.5 * 108 km)