"Joining Fists…!!" (合わせる拳…!!, Awaseru Kobushi…!!, Viz: Fist Bump) is chapter 643 of the original Naruto manga.
Yin-Kurama questions Minato about whether or not he had always intended to have his son take care of the situation for him, questioning whether that was the reason behind sealing its Yang half into him. The fox then tells Minato it was not his fault that his wife died, and Naruto becoming a jinchūriki was not inherently bad. Back on the battlefield, Naruto and Tobirama regroup with the others, and while Naruto explains the fact that senjutsu had been effective against their opponent, Tobirama muses to himself that Naruto's ability to work with his Flying Thunder God Technique and use of senjutsu reminded him greatly of fighting alongside his brother. Recovering from his injuries, Obito lamented that even as the beast's jinchūriki, he could not afford to act carelessly, before casually continuing on with the Eye of the Moon Plan. Creating an enormous tree with four opened flowers, Obito creates four Tailed Beast Balls intent on destroying the remainder of the Allied Shinobi Forces in one fell swoop. As the shinobi scramble to deal with the situation, Tobirama noted that even if he and Minato used the Flying Thunder God Technique to teleport the attack away, they could each only carry two, only halving the threat. Calling out to his brother, Hashirama once again beseeches Madara to put their battle off so that he can deal with the situation, but the Uchiha notes that they were reincarnated and as such it would not matter if they were caught in it. He then challenges his Senju rival to defeat him if he wanted to help. One of Hashirama's remaining wood clones calls out to the Alliance to not lose their nerves and explains his strategy to them. However, Obito with the use of the chakra receiverserects a barrier, intent on trapping the shinobi with the attack. As they readjust their strategy to their new predicament, Naruto notes that he had a plan but wasn't sure it would work. He then proceeds to ask Minato to bump fists with him, connecting the two halves of Kurama. The Yang half of Kurama asks its Yin half to help it by providing it with some chakra, to which the Yin half noted that it begging itself for help was weird. As Obito — wrapped in a defensive cloak — continues to decry Minato exclaiming that it would soon be the anniversary of Minato and Kushina's death. Noting that it only meant that tomorrow was also his birthday, Naruto tells Obito that the world would not end because he still existed within it. Donning his Tailed Beast Mode mantle, he calls out to his father who marvelled to Kushina that their son had grown up, responds emphatically.