Qam-Chee was a city on the Klingon homeworld of Qo'noS. It was there, "a thousand years ago", that Kahless and the Lady Lukara fought a pitched battle in the city's Great Hall against the soldiers of Molor. While the rest of the city's garrison fled before Molor's five hundred soldiers, Kahless and Lukara stood their ground and defeated the forces. Shortly after their victory the two began their great romance, the stuff of Klingon legend. (DS9: "Looking for par'Mach in All the Wrong Places")
In DS9: "Looking for par'Mach in All the Wrong Places" taking place in 2373, Worf enthusiastically mentioned the events in Qam-Chee to have happened "a thousand years ago." This would appear to be somewhat of a contradiction as TNG: "Rightful Heir" and DS9: "The Sword of Kahless" both state, that Kahless lived five hundred years earlier. Either Worf "rounded" the number of years in his enthusiasm, or Molor and Kahless were at least 500 years old, which, while the maximum life span for Klingons has never been clearly defined, seems to be without precedent. Another solution would be that Worf counted in Klingon years, as DS9: "Soldiers of the Empire" states 2373 to correspond to the Year of Kahless 999.
The Star Trek Customizable Card Game names a vessel after this city.