"Reached" (届いた, Todoita) is chapter 622 of the original Naruto manga.
As Madara and Hashirama continue their conversation by the riverside, the banter between them is cut short when a body washes up near them. Moving to check the corpse out, Madara comes to realise that Hashirama is a shinobi as he stood atop the water. Upon further inspection of the body, Hashirama realises that it belonged to a member of the Hagoromo clan and he, and Madara decide to leave the riverbank. Heading back home, Hashirama is informed that Kawarama had been killed on the battlefield, and as they stood by the graves with his youngest brother Itama openly weeping, Hashirama questions his father about the fact that innocent children were being sent on the battlefield to die. Affronted by this, Hashirama's father hits his son telling him that saying such things were an insult to Kawarama's memory who had died a proud shinobi on the battlefield. Unable to agree with this, Hashirama decries these actions further, but before his father can hit him again, Tobirama intervenes offering that Hashirama was grieving and pleaded for their father's forgiveness. Later, the three brothers spoke of bringing peace to the world. Some time later on the battlefield, Itama would lose his life after being confronted by five members of the Uchiha clan. Affected deeply by the loss of his brother, Hashirama went back to the riverbed when he met Madara again, who caught him crying. At first, Hashirama refuses to share the reason for his shedding tears, but he eventually explains that his little brother Itama, had died. When asked if he had any siblings, Madara answers he's one of five brothers, then correcting himself, he noted that he was one of five brothers. After Madara finally manages to skip the rock to the other side, the two talk about the death of their relatives and Madara offers words of comfort about a better future.