Fire Release: Great Fireball Technique

A technique where chakra kneaded inside the body is converted into fire, and expelled from the mouth in a massive orb of roaring flame. The scope of the attack is altered by controlling the volume of chakra that is mustered. The released flames will engulf their target, and leave a crater on the ground's surface. The fireball is normally blown through a ring made by the thumb and index finger of the user. However, Sasuke and Itachi are seen doing this technique without making a ring over their mouth.

According to Kakashi Hatake (in the anime Part II), the Fire Release: Great Fireball Technique was originally created by the Uchiha clan, becoming one of their favourite moves with which they became very adept. The Uchiha clan also uses the Fire Release: Great Fireball Technique as a "coming of age" technique. This technique apparently requires more than average chakra reserves and most Genin should not be able to do this technique.

Trivia

 * In the video game Naruto Shippūden: Dragon Blade Chronicles, Naruto's Dragon Blade enables him to perform this jutsu (though he refers to it as Fire Shot) despite Fire not being his Nature Type.
 * In another video game Naruto Shippūden: Ultimate Ninja 4, after learning all other jutsu Kakashi after beating him in battle, he will teach you this technique and allows you to customize it to characters in free battle.