The Chūnin Exam Stage 2: The Forest of Death

is episode 27 of the original Naruto anime.

Synopsis
Anko briefs the candidates on their objectives for the second portion of the Chūnin Exams. The test is structured such that at least half the teams will be eliminated. Before entering the Forest of Death, all teams will be given either a heaven or an earth scroll. Once inside the forest, the Genin must take the other scroll from another team. Only those that make it to the tower in the centre of the forest with both scrolls will advance to the next stage of the exams. Anko hands out the scrolls and opens the forest gates. As they enter, Naruto's team is attacked almost immediately.