Early in the Galactic Civil War, the attack on Kashyyyk unfolded on the Wookiee homeworld of Kashyyyk. The Galactic Empire's military forces launched an offensive against a secretly established Rebel Alliance observation post. The Rebels successfully fended off the initial Imperial assault, which led the Empire to commence a second attack. This subsequent Imperial effort resulted in the capture of Kashyyyk, although some Rebel troops were able to escape the planet.
Prior to the Battle of Yavin, the Rebel Alliance had covertly constructed a small outpost on the Wookiee homeworld of Kashyyyk, managing to do so without the Galactic Empire's awareness. This outpost included a planetary communications array used for monitoring local transmissions, as well as a barracks to accommodate a small contingent of soldiers.
After a Rebel patrol team, dispatched into a nearby forest for a routine perimeter check, went missing, another patrol, Squad Three, was sent out to locate the lost unit. The disappearance of the Rebel squad was actually part of a scheme orchestrated by the local Imperial forces to pinpoint the location of the concealed Rebel outpost. The Empire had deployed a communications jamming device with the intention of drawing the Rebels out. The destruction of this device confirmed to the Imperial commander that a Rebel presence existed, and an immediate attack on the outpost was initiated.
Once the jamming device was destroyed and communications were restored, all Rebel patrols were ordered back to defend the base. The commander was able to infer that their position had been compromised and that enemy forces were approaching after discovering Imperial markings on the remnants of the device. Shortly after, an Imperial assault force, which included TIE Maulers, stormtroopers, and All Terrain Scout Transports, located and attacked the Rebel outpost. The attack was pushed back, and the Alliance ground forces were then able to seize several Imperial landing zones located deeper within the forest.
Following the Rebel capture of the last Imperial reinforcement point on the planet's surface, the Imperial Navy dispatched a task force. This force consisted of four Tartan-class patrol cruisers and two Acclamator-class assault ships, along with their TIE/LN starfighter escort. Upon entering the star system, the Imperial ships destroyed the small orbiting space station, which the Rebels had recently occupied and renovated. Despite its dilapidated state, the station was sufficiently functional to provide a minimal defense. During the subsequent orbital engagement, the station, along with a Rebel EF76 Nebulon-B escort frigate and multiple fighter and bomber squadrons, was destroyed. This led to a complete abandonment of Kashyyyk by the Alliance, resulting in a retreat to their base on the planet Bothawui.
After the orbital conflict, the Empire sent a scouting force to the planet to retake Kashyyyk after the Rebel Alliance was compelled to evacuate. The remaining Rebel forces had retreated to the main Alliance Fleet, which was stationed above Bothawui at the time. Mon Mothma, the Rebel leader, was relieved to see that some had survived Kashyyyk, but explained that the credit-depleted Alliance desperately needed new sources of revenue to withstand future Imperial attacks.
The Rebels then established a new base on Ryloth, but it was soon discovered and overrun by an Imperial assault, due to intelligence acquired by the Empire from the starship logs of a captured Rebel smuggler. Shortly thereafter, an Alliance Special Forces company was sent to assist another Rebel outpost on Tatooine, which was under siege by the Imperial Navy and Army.
This battle appears as one of two combat training levels featured in Star Wars: Empire at War, a real-time strategy video game developed by Petroglyph and released by LucasArts in 2006.
In some instances, the player may receive 10,000 credits at the start of the Space combat training level. This allows the player to build a Level 3 Space Station and supplement their existing forces with more Victory-class Star Destroyers and TIE Scouts. If the Forces of Corruption expansion is installed, the player can even upgrade their Space Station to Level 4 and build Immobiliser 418 cruisers and TIE Defenders.