Kostner was a strategically important Klingon planet.
History and specifics[]
The planet Kostner was the Klingon's base for expansion "westward" beyond Federation borders in the 23rd century. It was an agriculturally poor planet, but had significant natural resources and therefore was a major producer of raw materials and crystals. The Klingons established a major base at Kostner, complete with orbital ship repair facilities. It was a planet that the Klingons were turning into a defense complex. (FASA RPG module: The Klingons: Game Operation Manual)