"The Wager…!!" (賭け…!!, Kake…!!) is chapter 159 of the original Naruto manga.
Recognising the Rasengan, Tsunade creates a fissure in the ground. Naruto falls in and the Rasengan is forced into the ground. Seeing that it is incomplete, Tsunade reprimands Jiraiya for teaching him such a technique as it just give Naruto unwarranted hope. Determined to prove her wrong, Naruto vows to master the Rasengan in three days. Tsunade offers the deadline of a week instead. If he can stay true to his word, he can have her priceless necklace; if he fails, she gets his wallet. Naruto accepts and runs off to start training. Tsunade and Jiraiya get drinks, during which Jiraiya reveals he is aware of some deal she has made with Orochimaru. If she decides to help him, Jiraiya states he will not hesitate to kill her. He then observes that Naruto is very much like her brother Nawaki, which Shizune elsewhere decides to tell Naruto about.