Siege on Syni IV

"The Alliance commander thought he had cut the remote system off via sub-space jamming. Unfortunately, when sector command realized the garrison wasn't transmitting, they dispatched a Star Destroyer to investigate. Syni IV remains under martial law."

- Major Viran Qol, lecturing cadets at the Alliance Officer's Candidate School

During the Galactic Civil War, a siege took place on Syni IV.

The siege
During the Galactic Civil War, a Rebel commander attempted to besiege an Imperial garrison on Syni IV.

The Rebel commanding officer first cut off the remote Syni system by jamming subspace communications. He then besieged the garrison by carefully remaining outside the garrison's weapons range and launching over-the-horizon artillery barrages every time the garrison tried to sally.

While the jamming prevented communications, the absence of contact from the Wild Space planet led the Imperial sector command to send a Star Destroyer to investigate. As a result, the Rebel forces were slaughtered.

In 3 ABY, at the time of the Battle of Hoth, Syni IV was still under martial law.

Aftermath
"A few Sectors Commands have attempted to overtly assault garrisons, or besiege them in remote areas, and they ended in worse than failure&mdash;they were slaughters."

- Major Viran Qol

Shortly after the Battle of Hoth, Major Viran Qol of Alliance Special Forces used the siege on Syni IV as an object lesson during one of his lectures at the Alliance Officer's Candidate School. The operation was a prime example of why besieging an Imperial prefabricated garrison base was a strategy that should be avoided, as it usually resulted in failure.