The Sharingan (写輪眼, The Sharingan? literally "Copy Wheel Eye," English "Mirror Wheel Eye") is an eye technique (瞳術, dōjutsu?) that naturally occurs in a select few members of the Uchiha clan. The Sharingan is thought to be descended from the Byakugan,[30] but grants the user different abilities and a different insight. The Sharingan does not automatically appear from birth in a user; instead, it will usually appear when the user is in a life-threatening situation, where the power of the Sharingan could save them. After this first appearance, the user can then activate the Sharingan any time they wish. The power of the Sharingan is judged through the number of tomoe in the eye, with a maximum of three in each. The characters that possess the Sharingan in the current Naruto storyline are Sasuke Uchiha, Itachi Uchiha, Madara Uchiha, and Kakashi Hatake.