I say, and with God's success: There are many evidences supporting the issue, which Al-Laknawi elaborated on in his book "Tuhfat al-Talabah" regarding wiping the neck. Among them is the narration from Talhah bin Masrif from his father from his grandfather, may Allah be pleased with him: "I saw the Messenger of Allah, peace be upon him, wiping his head once until he reached the nape of the neck," and the nape is the back of the head, as mentioned in "Al-Misbah Al-Munir" 2: 495. In another narration: "the beginning of the nape" in Musnad Ahmad 3: 481, Sunan Abu Dawood 1: 32, and Sharh Ma'ani Al-Athar 1: 30, and Allah knows best.