The Lightning Blade is an enhanced form of the Chidori with the same effects and drawbacks, but more power. Kakashi learned how to perform this ninjutsu before Kakashi Gaiden but was not able to sustain it long enough to connect. He finally made it work after a lightning bolt struck him and gave him enough power to use it and take revenge for Obito Uchiha's death. It is also said that Kakashi cut a lightning bolt in half with this technique. The first time he used it and the legend of him splitting said lightning bolt are speculated to be the origin of its name. Because the Chidori is already powerful on its own, the Raikiri requires much more chakra and better chakra control, which is examplfied in its appearance. The Chidori appears as simply a mass of white electrical chakra in the user's hand, the Raikiri is more focused and blue. Like the Chidori, Kakashi can use the technique four times a day, which is an incredible feat, considering the intensity and chakra requirements