Bava Batra 104: Specifically Measured with a Rope, More or Less

Our daf begins with the Gemara of a new Mishna which discussed how one must respond when there is an overpayment or an underpayment; a slightly larger measure or a slightly smaller measure.  One of the key components is identifying whether or not the seller was specific about how much was being sold. 

The Gemara focuses on examples of exact measures of seed.  When a sale is slightly more or less (in specific measures) in a field, in a garden, or in other specific places, there are different forms of restitution.  It seems that the rabbis are concerned about people attempting to get away with inappropriate exchanges.  Sometimes these sales are private, but in other cases the public is affected, like in the case of a public thoroughfare through a privately owned field.  It is significant that the rabbis are equally concerned with wrongdoing regardless of whom/how many people are affected.  

We end today's daf with a new Mishna.  It teaches about what should be done if a seller contradicts himself in his contract.  He might say that he is selling a plot of land that was precisely measured with a rope, more or less.  The "more or less" nullifies his earlier statement about a precise measure.  To correct this error, there must be at least a quarter-kav per se'a surplus.  Similarly, if the seller says that he is selling a plot of land that has been measured more or less precisely with a rope, the precise measure by a rope comment nullifies the "more or less" comment.