Dual-phase lightsaber was a special variant of lightsaber that used a combination of focusing crystals to create a blade that could extend up to double 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, dual-phase lightsabers also had a blade-width adjust. Gantoris wielded such a lightsaber,[2] as did Corran Horn.[3]
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. This style of lightsaber was so antiquated that by the time of the Yuuzhan Vong War they were considered a sign of old and outdated jedi, which Ganner Rhysode frequently pointed out to Corran Horn during their Mission to Bimmiel.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 it's time in the Rise of the Empire era.