The Beginning of the Crimson Spring (紅き春の始まり, Akaki Haru no Hajimari) is chapter 668 of the original Naruto manga.
Immediately beginning their attempts to dissuade Guy from his decision, his comrades soon abandon this as a fruitless endeavour. Comforting his pupil by telling him that this was no time to look sad, Guy dashes forward to confront Madara once more, sticking his thumb into his chest as he went and opening the Eighth Gate. Remembering his father Might Duy in these final moments before the confrontation, he remembers how he had lived his life, and in turn, how Guy had loved his own life, passing on principles of unwavering loyalty and true inner strength right down to the very last moment of his life where Duy was able to ultimately protect his son, and his team-mates Ebisu and Genma, from a generation of the Seven Ninja Swordsmen of the Mist. Though Madara tried to trivialise Guy's incoming onslaught as nothing more than leaves that fall and rot in autumn, Guy corrected him, declaring that those leaves would become nourishment for the new leaves on the tree before reaching his target and attacking him with the Evening Elephant.
This chapter was most likely made in honour of Kishimoto's father, who passed away around the time this chapter was released.