How did Imam Khalaf al-Aashir come to have a unique recitation from his shaykh Hamzah, despite their agreement on many recitations, and what is his chain of transmission, and where does the difference lie?

Khalaf al-Ashir differed from his teacher Hamza in the selection of 120 letters (harf), but he did not deviate from the reading of the Kufans except in one letter, which is Allah's saying in Surat al-Anbiya': (And [it is] forbidden for a town). He also transmitted from him the silence (sakt) between the two surahs. His chain of transmission (sanad) for the reading was connected to the Prophet, peace be upon him. He read to Sulaym, Hamza's companion; to Ya'qub ibn Khalifah al-A'sha, Abu Bakr's companion; and to Abu Zayd Sa'id ibn Aws al-Ansari, al-Mufaddal al-Dabbi's and Aban al-Attar's companion. He also narrated the letters from Ishaq al-Musayyibi, Nafi's companion; from Yahya ibn Adam, from Abu Bakr; and from al-Kisa'i. This selection of his is not considered an anomaly (shudhudh) but rather a preference for well-established (mutawatir) readings that he received from trustworthy teachers.