A new mishnah! On the sale of a field with demarcations of the property, where the buyer can hold the seller to those specifications, with a one-sixth margin of error (give or take, which is the bulk of the discussion). Plus, whether one-sixth exactly should be treated as more or less than one-sixth, which are respectively defined with halakhic conclusions. Also, the case of brothers who drew lots to determine the portions each received of their inheritance. With parallels to the division of the land of Israel among the 12 tribes, under the guidance of the Urim ve-Turim -- but there's no reason to think the brothers' decision would be contested, which is an easier lottery, such as it was.