The planet Kolaador, located in the Kolaador system of the Outer Rim Territories was a rocky world, with a number of canyons filled with crystalline spires. The Alliance to Restore the Republic established a Pilot Training Center on the planet prior to 0 BBY, using these canyons as challenging training runs for their pilots. Among those trained at the facility was Rookie One.
During the Galactic Civil War, the Galactic Empire attacked Kolaador, with a force led by three Star Destroyers. Deploying both TIE fighters and TIE Interceptors from orbit, the Imperials engaged Rebel forces consisting of A-wing and X-wing starfighters in dogfights among the planet's crystal canyons. Among the Rebel forces defending the base, was Kolaador graduate, Rookie One, flying an X-wing.
This battle is based on the box cover art for Star Wars: Rebel Assault, a LucasArts video game released in 1993, which was reused for the Rebel Assault: The Official Insider's Guide. The artwork by Greg Winters depicted a battle on the planet Kolaador, even though no such battle occurred in the game itself; Kolaador was only used for a training mission, with no combat involved. This artwork was later reused by Topps in their 1995 Topps Star Wars Galaxy Series 3 set of trading cards, released in 1995. The card had an accompanying description on its back specifying Rookie One's involvement, as well as reinforcing the event within the Legends timeline. There is, however, no indication of the chronological placement of the battle, except that it must be after Rookie One's training there.
Excerpts from the Journal of a Rebel Pilot mentions Rookie One being back in the same bar of Kolaador Rebel base three years later, long after Anchorhead Base was destroyed. This visit may be linked to the above-mentioned battle, linking it to the year 3 ABY.