Kilayim, Chapter 6, Mishnah 6. Our Mishnah discusses the law of piskei aris: a trellis (aris) that was destroyed in its middle, leaving a gap between its two remaining sections. The question is: from what measurement onward is the space between them considered sufficiently distant from both sides of the trellis, so that it is permitted to sow other seeds within it.
The words of the Mishnah:
"Piskei aris - shemoneh amos v'od" - the measurement of the gap in a broken trellis, in order that one may sow within it, is eight amos and a bit more. Regarding this measurement the Mishnah comments: "V'chol midos she'amru chachamim bakerem ein bahem v'od, chutz mipiskei aris" - of all the measurements that the Sages gave in the laws of kilayim of the vineyard, there is not one to which the addition of "and a bit more" was attached, except for the case of piskei aris.
Defining piskei aris:
The Mishnah explains: "Elu hen piskei aris" - this refers to a trellis that was destroyed in its middle and broken, "v'nishtayer bo chamesh gefanim mikan v'chamesh gefanim mikan" - five vines remained on the latticework on one side of the break and five vines on the other side, and in the middle a gap remained.
The measurement of the gap:
"Im yesh sham shemoneh amos - lo yavi zera l'sham" - when the gap is exactly eight amos and no more, one may not sow in that area.
"Shemoneh amos v'od - nosen lo k'dei avodaso v'zorea es hamosar" - when there are eight amos and a bit more, one sets aside the space needed for working the vines on each side, and the remainder may be sown.
What is the measurement of k'dei avodaso?
This measurement depends on the dispute among the Tannaim in the first Mishnah of the chapter, whether a trellis has the status of a vineyard or not:
According to the opinion that a trellis has the status of a vineyard: one must distance four amos from each side of the trellis, and in this way the only area left permitted for sowing is the "and a bit more" - whatever lies beyond the eight amos.
According to Rabbi Yochanan ben Nuri: a trellis is not like a vineyard, and therefore there is no need to distance four amos from it, but only the distance required from a single vine - six tefachim. Accordingly, in a place where there are eight amos, one sets aside six tefachim on each side and sows the rest. Even so, eight amos and a bit more are required as the condition for the very permission to sow in that area.
This is the law that this Mishnah teaches us.