Decryption

is episode 154 of the Naruto: Shippuden anime.

Synopsis
This episode opening begins with the decryption of the code Jiraiya left on Fukasaku's back. Shikamaru questions Naruto to see if any ideas for the code's decryption pop into his mind. Immediately, he realized that the first number '9' was a writing quirk of Jiraiya's and was actually a 'ta' in katakana. 'Ta' lead them to Jiraiya's Icha Icha series and from there, Shiho, Naruto, Shikamaru, and Kakashi decoded the message to mean "The real one's not among them." Later on, the decryption team relays the message to Tsunade, and it is decided that Naruto will learn the ways of a Sage. He is taken to Mount Myōboku through the Reverse Summoning Technique initiated by Fukasaku through Naruto's contract with Gamakichi. At Mount Myōboku, Naruto begins to learn about sage techniques after having one of Shima's meals.