"Kakashi Chronicles ~ Boys' Life on the Battlefield ~ Part 2" (カカシ外伝～戦場のボーイズライフ～前編, Kakashi Gaiden ~ Senjō no Bōizuraifu ~ Kōhen) is episode 120 of the Naruto: Shippūden anime.
The enemy tries to stay away from the "Yellow Flash", but it was too late. Kakashi and Obito go to save Rin instead of completing their mission. Kakashi saves Obito from another enemy ninja but gets a permanent scar on his left eye and uses Rin's healing kit he got as a gift to stop the bleeding. The enemy ninja camouflages in the forest undetected and tries to kill Kakashi but fails when Obito awakens his Sharingan. Kakashi and Obito release Rin from a genjutsu and try to escape but rocks come crashing down and crush Obito. Obito remembers how he hadn't got Kakashi a gift and gives him the Sharingan in his scarred eye. Kakashi and Rin escape and Minato apologises that he couldn't make it in time. The war ends with many deceased and nameless ninja and Obito gets his name engraved on the memorial stone on the battle of Kannabi Bridge.