A failed Rebel Invasion of Kashyyyk took place in 1 ABY, during the Galactic Civil War. An Imperial starfighter force led by Darth Vader prevented Rebel Alliance troops to land on Kashyyyk and liberate the planet
In 1 ABY, the Rebel Alliance assembled a fleet and troops in order to invade and liberate the Wookiee world of Kashyyyk from the Galactic Empire and Trandoshan slavers. However, unfortunately for the Alliance, the Empire discovered the plan right before the invasion started. Darth Vader, who was present on Kashyyyk at that moment, therefore gathered Imperial starfighters and pilots to ambush the Rebel fleet. Vader did not participate in the battle himself but he provided his own Eta-2 Actis-class interceptor to an Imperial ace pilot who previously served under Admiral Krieg.
Although Imperial pilots had barely the time to take off and met in the Kashyyyk system, they were ready to fight when the Alliance starfighter jumped out hyperspace. A squadron of X-wing starfighters first arrived in the system. The surprise was total for the Rebel pilots who expected to attack Kashyyyk by surprise. In the ensuring battle, the Alliance suffered heavy casualties, particularly from the Imperial ace who piloted Vader's interceptor.
Rebel troop transports and support ships later arrived in the system, but they were soon joined by a group of Imperial TIE bombers. Due to the loss of most X-wings in the first stage of the battle, the Alliance starships were completely vulnerable to Imperial fighters and bombers. All the Rebel troops were killed in their transports before they could even approach the planet Kashyyyk. The battle ended when the remaining Alliance ships were destroyed.
The destruction of the Rebel invasion force in space totally abolished any hope to liberate the world of Kashyyyk in the short-term. The Wookiee planet would only be freed three years later by the New Republic, after the Battle of Endor.
The Rebel Invasion of Kashyyyk appeared in the 2003 video game Star Wars Galaxies, a massively multiplayer online roleplaying game developed by Sony Online Entertainment and published by LucasArts, prior to its closure on December 15, 2011. The battle was added to the game with the Rage of the Wookiees expansion pack, released on May 5, 2005.