The first of the two Kinjutsu passed down through the generations within the Ketsueki Clan. Only those who have mastered Blood Manipulation can use such a potent jutsu. The target's blood is made more potent by the user and then some portion of it is consumed. The amount that must be consumed varies, but is rarely enough to cause serious harm to the target. When Mori used the technique to acquire the Sharingan from Itachi Uchiha, he only drank about a teaspoon of blood.