"Head" (頭脳, Zunō) is chapter 613 of the original Naruto manga.
Summary
Following the strategy from Headquarters, the Allied Shinobi Forces attack Madara and Obito with a barrage of attacks. Madara notes that their plan to attack the Ten-Tails' mind was a basic step in taking out an opponent, but they must actually stop the beast first. At that moment, the beasts' tails burst from the ground, topped with giant hands, to literally throw the shinobi back. When the dust settled, the Ten-Tails' true form is revealed. Back at HQ, Ao and Shikaku notes that the Sensing Sphere's shape greatly distorted, meaning their initial plan to hold the Ten-Tails had failed. Trying to come up with a plan, Shikaku asked Kakaskhi to confirm something from their previous battle with the Ten-Tails. With its power grown exponentially, Madara had Obito and himself strengthen the bond with the Ten-Tails to keep it under their control brfore showing the Allied Shinobi to true power of the beast. As the Ten-Tails prepared for an attack, Kitsuchi, use Earth Release to knock it off balance, sending the fired Tailed Beast Ball flying in a random direction far away from them. The shock of the attack even managed to shake the two Uchiha, noting that their control over the beast isn't complete. Obito however charges another Tailed Beast Ball and fires it again, at a random far target. Shikaku informs the others at HQ that the reason for it's random aim, is to show the Allied Forces that despite being on the battlefield to protect the world, nothing was safe from the Ten-Tails. Focusing the Ten-Tails on it's legs, it charged a final Tailed Beast Ball and aimed at the Headquarters. Knowing that escape wouldn't save them from such a blast, Shikaku came up with a new strategy to stop the Ten-Tails and had Inoichi connect him with the forces on the front lines. With his final strategy given, the Tailed Beast Ball wiped out the Headquarters, killing everyone inside. With this, a satisfied Madara repeats that it is only a basic strategy to target the opponents mind.