Bell Test

The bell test is a form of examination that is given to the Konoha Academy Students who have managed to graduate from the academy. The jōnin who has been assigned to test out the three-man cell will use this test to determine whether the three students are worthy of being officially promoted into genin, sent back to the academy for further training, or even dropped from the program altogether for overly poor performance. It is unknown if all Konoha teams are tested by such a test, as only Teams Hiruzen and Kakashi were seen performing it.

Details
The test is for the each student to take one of the two bells from their to-be teacher within a set time limit in order to pass. Since there are three students, it would seem that one of them will be sent back to the academy no matter what. This, however, is a ruse to test out whether the three can work as a team: if they ignore the fact that only two bells are available and be willing to work together, they might have enough skills to take the bells, and be allowed to pass.

History
When Hiruzen Sarutobi performed this test on his students, both Orochimaru and Tsunade managed to take the bells, while Jiraiya did not and was tied up to a stake as punishment.

When Kakashi Hatake performed it years later on Naruto Uzumaki, Sasuke Uchiha and Sakura Haruno in the Third Training Ground, he forbade any of them from eating breakfast beforehand, and that whoever fails to get a bell does not get lunch either, instead will be tied to the stake and watch the others eat. None of his students were able to take it due to their refusal to work together, with Naruto even caught trying to eat the lunch sneakingly. Kakashi nearly expelled all three from the academy for their lack of teamwork, but they redeemed themselves by breaking his order of not to feed Naruto, showing team spirit.

Two and a half years after Team Kakashi was formed, Kakashi once again performed the Bell Test on his students to evaluate their improvement, but since Sasuke has defected from the village, Naruto and Sakura needed only to take a bell each. Having trouble defeating Kakashi despite their improvements, they resorted to threatening to spoil the ending of Kakashi's favorite novel, Icha Icha Tactics, and then each took a bell for themselves while he was distracted.

Trivia

 * In the third Naruto Shippūden movie, the bells used by Kakashi for the exam were damaged, so he gave them to Naruto to fix. The bells served as an inspirational reminder of how their team was formed, which gave Naruto and Sakura great resolve to save Kakashi from Hiruko while defying Tsunade's orders not to.