40화: 오로치마루가 나루토를 자극해 구미오의 기가 새어나가고 변신이 시작된다.

40

Yamato signals Naruto, Sakura and Sai to appear on the bridge. On seeing Naruto, Orochimaru begins mocking him and compares him to Sasuke, which causes the Nine-Tails's chakra to leak from an enraged Naruto's body and ascends him to a Three-Tailed form. Meanwhile, Yamato remembers Jiraiya speaking of the appearance of number of tails on Naruto during their training, and had specifically warned of Naruto's Four-Tailed transformation. (Source: Wikipedia) Tenchi Bridge Reconnaissance Mission arc: (8/21)