Syni IV was a planet in the Syni system, in Wild Space. During the Galactic Civil War, Rebel Alliance forces attempted to besiege the planet's Imperial garrison. The Rebel commanding officer cut off the system by jamming subspace communications and bombarded the garrison using over-the-horizon artillery from outside the garrison's weapon range. While the jamming prevented communications, the absence of contact from the planet led the Imperial sector command to send a Star Destroyer to investigate. The planet was still under martial law when Major Viran Qol of Alliance Special Forces used the world as an object lesson during his lecture on Imperial prefabricated garrison bases.