The Ultimate

is episode 401 of the Naruto: Shippūden anime.

Summary
Shira accepts Lee's offer to fight him one on one. The two begin their battle, and as they exchange fierce attacks, both seem to be equally on par with one another. Observing the battle, Neji notes that Lee will sustain more damage due to Shira having a much superior physique. Eventually noticing that he is at a disadvantage, Lee attempts to open the Eight Gates, but finds that he cannot; Shira having blocked his tenketsu, therefore stopping his chakra flow. Shira then resorts to attacking silently, further putting the pressure on Lee. Remembering one of his training sessions with Guy, Lee is able to predict and counter Shira's moves. His tenketsu is ultimately released by Shira, and thus, Lee is able to open the Eight Gates once more. Shira activates the Seven Heavenly Breaths, his own self-made equivalent of the Eight Gates, enhancing his lung capacity and his attacks to another level. Though both now seem evenly matched, Lee soon gains the upper hand after activating the Fifth Gate of Limit. Ultimately, this clash culminates in Lee's victory. Elsewhere, Gaara is informed by his subjects that Kegon and Yōrō are actually jōnin in disguise. Gaara orders them not to tell anyone else about this and begins to spy on Team Fū, using his Third Eye. However, to his shock, Fū quickly found his sand eye, forcing him to cancel the technique. Gaara then realised the truth about the kunoichi.