"The Second Step" (第二段階, Daini Dankai) is chapter 152 of the original Naruto manga.
By spinning chakra with both of his hands and forcing the energy into the water balloon from opposing directions, Naruto is able to pop it. Though unorthodox, Jiraiya is impressed and tells him about the second step to learning the Rasengan. The second step is very similar to the first; Naruto must pop a rubber ball. Since the ball is much sturdier than the balloon, he will need to improve the Rasengan's strength. Naruto once again struggles with the step as he cannot burst the ball, only managing to create a hole in it. Content with this development, Jiraiya draws a mark on the palm of his hand to help.