Galactic Sector 973 was the Mutter's Spiral sector where the War Lord homeworld was located, although the planet used for their War Games was in another sector. (TV: The War Games)
The War Lords took war-like species from across the sector to test their aptitude, including beings from the homeplanet of the Ulk-Ra and from Earth, (PROSE: War Crimes) although Earth was stated to be in Sector 8023. (TV: Logopolis)