The Vallusk Cluster conflict was initiated by naval units of the Rebel Alliance six months following the Battle of Yavin in 0 ABY. Its purpose was to provide support to the main fleet stationed at Yavin.
Admiral Gial Ackbar, representing the Mon Calamari within the Alliance, consented to engage Imperial forces within the Vallusk Cluster. Several other blockade zones were targeted to obscure the Alliance's true intentions from Imperial commanders. The objective was to relieve pressure on the Gordian Reach sector, creating an opening for the evacuation of Rebel personnel and their fleet from Massassi Station.
The forces commanded by Admiral Ackbar, consisting of Mon Calamari Star Cruisers and CR90 corvettes, initiated their assault in the Vallusk Cluster. This was quickly followed by two additional attacks in other sectors of the blockade. Amise Griff, the Imperial Admiral overseeing the blockade while Darth Vader's Executor was undergoing maintenance, was not deceived by the Mon Calamari's maneuvers. He chose not to reinforce his under-fire units. Instead, he attempted to prevent the main Rebel fleet from exploiting the opening, aiming for a personal victory, a decision that ultimately led to his demise.
The exact number of casualties suffered by each side during the conflict remains unknown. However, the Mon Calamari considered the operation a success. This engagement also marked the first overt declaration of allegiance between the Mon Calamari and the Rebel Alliance, despite previous encounters with the Empire.