In the mirror universe, the SoHcha Fleet Yards were the largest, most advanced shipyards of the Klingon Empire. The yards were located in the SoHcha system, deep inside Klingon territory. The facility boasted heavy fortifications and was well-patrolled, making it the best defended shipyard of the Empire. Assignment to the fleet yards, albeit important to the imperial war machine, awarded little prestige.
In 2378, Memory Omega and the Terran Rebellion led a joint attack on the fleet yards to destroy them and cripple the Empire's military infrastructure for most of the 2380s. The assault was led by General Miles O'Brien of the Defiant}. Simultaneously, Earth was liberated by a similar strike. The entire SoHcha shipyards were obliterated when the Omegan fleet caused a protuberance on SoHcha's surface that blasted away all Klingon ships and structures. (ST - Mirror Universe novel: Rise Like Lions)