Jar’Kai was originally a style of swordplay that utilized dual blades, developed by the Yovshin Swordsmen. A similar dual-blade technique referred to as Niman was developed by the Royale Macheteros of the Kashi Mer monarchy.[2] Niman was adopted by the darksider group known as the Legions of Lettow during the First Great Schism, as well as the Jedi Order itself.[2] Niman was developed into the sixth form of Lightsaber combat, retaining its name,[2] while Jar’Kai became something of a blanket term for dual-blade combat.
It should be noted that the fourth form of lightsaber combat, Ataru, was also known to employ dual blades as part of its training regimen. Ahsoka Tano was a master in this form when she was only a Padawan, an accomplishment that Jedi Masters would have serious troubles in achieving.