The division (muqasama) here and the third are the same. If you divide by it, the estate is between them into six shares; the grandfather takes two shares. Then, the remainder of the half for the sister is completed from what is in their hands, which is three shares. One share remains for them [to be divided] by three, which is not valid, so you multiply three by the base of the issue, becoming eighteen, as al-Khiraqi said. If the children of the father exceed this, they are not increased beyond the sixth because the grandfather does not receive less than the third, and the sister does not receive less than the half, so only the sixth remains.

1027 - The Issue of al-Akdariyyah; he said: "If there is a husband, a mother, a sister, and a grandfather, the husband has the half, the mother has the third, the sister has the half, and the grandfather has the sixth."

Then, the sixth of the grandfather and the half of the sister are divided between them into three shares; the grandfather has two shares and the sister has one share. The obligatory share thus becomes valid from twenty-seven shares; for the husband are nine shares, for the mother are six, for the grandfather are eight, and for the sister are four. This issue is called al-Akdariyyah. No fixed share is assigned to the grandfather with sisters in any issue other than this. It is said: this issue was only called al-Akdariyyah for its "tadir" (turbidity/disturbance) of Zayd's principles regarding the grandfather; for he caused it to have 'awl (increase in the common denominator), yet there is no 'awl according to him in the grandfather's issues. He also assigned a fixed share to the sister with him, while he does not assign a fixed share to a sister with a grandfather, and he combined his shares and her shares, then divided them between them, and there is no parallel to that. It is also said: it is called al-Akdariyyah because 'Abd al-Malik ibn Marwan asked a man about it whose name was al-Akdar, and he issued a fatwa based on the school of Zayd but erred in it, so it was attributed to him. The scholars differed regarding it; the school of Abu Bakr al-Siddiq and his supporters is to exclude the sister, to assign the third to the mother, and the remainder to the grandfather. Umar and Ibn Mas'ud said: the husband has the half, the sister has the half, the mother has the sixth, and the grandfather has the sixth, and it increased (awlat) to eight. They assigned the sixth to the mother so that they would not prefer her over the grandfather. Ali and Zayd said: the husband has the half, the sister has the half, the mother has the third, and the grandfather has the sixth, and they increased it to nine and did not prevent the mother from the third; because...