Shattered!!!! (粉砕!!!!, Funsai!!!!) is chapter 598 of the Naruto manga.
Charging forward, Naruto attacks Tobi using a giant chakra arms which Tobi simply phases through, chiding the boy of thinking that he could defeat him on his own. As Guy tries to snap Kakashi out the shock brought on from Tobi's revelation, they see the masked man send three giant shuriken hurtling towards Naruto from the other dimension. Catching two of them on his tentacles, one of B and Gyūki's tentacles is cut by the third but is stopped by Naruto who retorts Tobi's earlier remark by telling he's never truly alone as he has Kurama and the others supporting him. Now motivated by Guy to act, Kakashi notes that he had to time the next use of his Kamui perfectly, despite Tobi chastising his "borrowed power" and stated intentions of showing him Kamui's true potential. Acting immediately, Tobi jumps into the air and sends out a number of chakra receivers which pierce B and Gyūki. Warning Naruto not to let them touch him as it sealed off the tailed beasts' power, Naruto creates a shadow clone while being protected by Gyūki. While a clone charged forward with the Rasengan, the original prepared the Tailed Beast Ball. As the clone prepares to attack, Kakashi seemingly warps away the Rasengan again while Tobi — seeing the same attack pattern — decides to attack the clone with one of the stakes, rather than having him go through him. With the clone seemingly dispelled, Tobi phases through the Tailed Beast Ball, and fully enters the other dimension. There, Tobi is shocked to see Naruto and realises that Kakashi had warped the clone there to wait for him. Declaring that he had nowhere to run, Naruto slams the Rasengan into Tobi's face, shattering the mask with Naruto asking his enemy who he is.
Interestingly, the way Naruto hits Tobi's face with the Rasengan breaking his mask in the process, mirrors the first time Naruto accessed Kurama's chakra early in the series, and punched Haku, also breaking his mask.