Sasuke starts off by dashing at his opponent with a Chidori in his hand. As he strikes his opponent, he uses Shape Transformation to extend the Chidori into a lightning spear that impales and hurtles the opponent into the air. Sasuke then increases the potency of the lightning, generating a powerful electric explosion at the end of the spear and sending the opponent back to the ground.
Shinsō (真槍) means "spear", but when the kanji are read separately, it means "true spear". True means that it's a real spear and not one used for training.