Valence System
Valence is the Sub-Sector capital and the 'gateway' into the Kaliduza Sub-Sector being a bottleneck from the single Warp Lane and the rest of the Systems in the Sub. It was made into fortress and fleet refitting base to assist with any defensive actions which may be needed to prevent a large scale Compliance Fleet from entering and commencing attack.
However while this System is potent against large scale invasions seen during the Great Crusade, smaller invasion fleets, like those now prevalent in the Heresy, are able to bypass the system due to their reduced requirement on a fleet anchorage which alone Valence provides. Still, such a system in either the Emperors or Warmasters pocket would prove to be very useful in creating a bottled up resistance force.