The TIE Advanced x1, or TIE/x1 was an advanced prototype starfighter touted as a replacement for the standard TIE Fighter and tested by Darth Vader at the Battle of Yavin and used by X1 during the Battle of Mustafar. At one point, the clone of Galen Marek stole Darth Vader's TIE Advanced x1 to escape Kamino.
While it never made it into production, many of its best design features were later incorporated into the TIE/sa bomber and TIE/In interceptor. Further development of the Advanced continued, eventually leading to the TIE Avenger and TIE Defender.
The TIE Advanced x1 featured a solar ionization reactor and paired twin ion engines like the original TIE Fighter. However, the x1 had an original spaceframe, with an elongated rear deck and reinforced durasteel-alloy hull. The x1's most important innovation was its "bent-wing" solar array wings, which had the advantages of increased surface area for more power while also reducing the craft's profile, compared to the TIE/ln starfighter's hexagonal panel wings.
Speed was only slightly improved due to the added mass of the vessel; a good deal of the extra power was bled off to the deflector shield generators. While less maneuverable than standard TIE fighters, it was more resilient in battle.
The TIE Advanced x1 had twin heavy blaster cannons in a fixed, front-mounted position, as well as a cluster missile launcher. In addition to its shields, it had a modest hyperdrive but no life-support systems. The target tracking system was also more sophisticated than the already formidable advanced targeting system on standard TIE craft, used to overcome the extremely powerful electronic jamming used by all combat craft to defeat target lock in battle. For best performance, the targeting system of the x1 required frequent adjustment in combat.