Nito Ryu: Raiden. Origins of the name

雷電

Sensei introduced the first technique of the second scroll of Jinenryu Nito Jyutsu.  The name Raiden means lightning.  Since the second scroll deals with the Tori striking first, this technique should be done "..as if thunder is rumbling and then BAM! you strike like lightning."  Sensei went on to mention that Raiden was the name of a famous Sumo wrestler from the Edo period. Here is the link to the Wikipedia page on Raiden.