- "Dual-phase blades seem to be something of a fad among Jedi at certain points."
- ―Luke Skywalker
A dual-phase lightsaber was a special variant of lightsaber that used one or a combination of focusing crystals to create a blade that could extend up to triple the original length with a simple activation. Unlike typical lightsabers, which often possessed a manual adjuster for reducing the blade emission, the dual-phased blade could be triggered in an instant, adding an element of surprise to catch an opponent off guard. Additionally, some dual-phase lightsabers also had a blade-width adjust. Gantoris wielded such a lightsaber, as did Corran Horn. Dual phase lightsabers could also have the ability to carry different crystals, and alternate between them at the user's discretion.
Records from circa 400 BBY indicate that Keiran Halcyon constructed a special dual phase lightsaber that could go from the standard 1.3 meters to a length of three meters with flick of a switch. Most dual phase lightsabers date from the Jedi Civil War, when lightsaber duels were common and the Sith were at the height of their power. As more beings became aware of the Jedi fighting skills and the Jedi themselves strove to end disputes without drawing their weapons, duels grew less frequent and dual-phase lightsabers went out of style. However, later on a new resurgence of these weapons happened. Darth Tyranus used a curved-hilt lightsaber with a dual phase function and Darth Vader used a dual-phase lightsaber during their time as Sith Lords. By the time of the Yuuzhan Vong War this style of lightsaber was so antiquated that they were considered a sign of old and outdated Jedi, which Ganner Rhysode frequently pointed out to Corran Horn during their Mission to Bimmiel. In The Jedi Path, Grand Master Skarch Vaunk wrote that the weapon was only good for surprise attacks, and while that was not technically true the opinion pointed out that it was very rare for its time in the Rise of the Empire era.
- The Jedi Academy Sourcebook (as double-bladed lightsaber)
- The New Jedi Order Sourcebook
- Jedi Academy Training Manual
- Star Wars Galaxies Trading Card Game – Threat of the Conqueror (Card: Dual-Phase Lightsaber)
- The Jedi Path: A Manual for Students of the Force