Hikariken (光剣, Literally meaning "Light sword"), is a technique that Renji created after creating "Amaterasu". After Renji used Amaterasu for the first time in battle, Renji noticed that he can't fight at full power in that form this is because Renji is a swordman, he thought "what's the use of heating my body if i am going to use my sword in the end" this is where he thought about using the same method to heat up his sword as well. To use this technique Renji would release great amounts of light from his hands and concentrate it all in his sword, heating it up greatly.