Kilayim, Chapter 6, Mishnah 1. This mishnah and the chapter that follows it deal with the concept of the aris - a trellis over which vines grow - and with the question of its status and its halachah.
What is an aris?
The mishnah opens with a question: "Ei zehu aris" - what sort of fence is considered a vineyard, from which one must keep a distance of four cubits exactly as one does from a vineyard? "Hanotea shurah shel chamesh gefanim betzad hagader shegavoah asarah tefachim" - one plants a row of five vines alongside a fence ten handbreadths high, and the vines climb over it. "O betzad charitz she'amok asarah tefachim verochav arba'ah" - a fence or a wall is not essential; even a trench ten handbreadths deep and four handbreadths wide falls under the same halachah. In such a case - "notnin lo avodato arba amos" - one allows a distance of four cubits, which is the area used for working the vine, and one may not sow within it.
The dispute between Beis Shammai and Beis Hillel - from where do we measure?
The vines are not necessarily right up against the fence, and there is a gap between the point where the roots of the vines enter the ground and the fence with its trellis. On this the Tannaim disagreed as to where the four cubits are measured from:
"Beis Shammai omrim, moddin arba amos me'ikar hagefanim lasadeh" - we measure from the roots of the vines themselves in the direction of the field.
"UBeis Hillel omrim, min hagader lasadeh" - the four cubits are measured from the fence in the direction of the field.
Some understand that the field in which one wishes to sow is on the same side of the fence as the vines are planted. According to this understanding, Beis Shammai are the stricter opinion, since measuring from the roots of the vines brings the starting point of the measurement closer to the field being sown than the fence does; Beis Hillel are the more lenient opinion, permitting one to measure from the fence, so that the area which must be left as a separation shrinks and one may sow sooner. Others explain that the discussion concerns a field located on the other side of the fence, and according to that reading Beis Hillel are the stricter opinion and Beis Shammai the more lenient one.
The view of Rabbi Yochanan ben Nuri:
"Amar Rabbi Yochanan ben Nuri, to'im kol ha'omrim kein" - anyone who holds that the law of four cubits by an aris is meant as a separation from the vines or from the fence, on the assumption that an aris is considered a vineyard, is mistaken. There is indeed a law of four cubits regarding an aris, but with a different meaning: "Im yeish sham arba amos me'ikar gefanim velagader" - if between the point where the vines enter the ground and the fence there is a distance of four cubits, "notnin lo es avodato vezorea es hamosar" - one sets aside only the working area, which is six handbreadths, and sows the entire remaining space. An aris has no status of a vineyard at all, and nothing more than six handbreadths from the vines is required - provided that there are four cubits between the vines and the trellis. That is where the measure of four cubits enters the picture.
And if there are not four cubits, the law reverts to the halachah we learned in the previous chapter regarding a winepress, an olive press, a planting, or a sheka - a hole in the ground - where Rabbi Yosei said that if it contains four cubits one leaves six handbreadths from the vine and plants, and if it contains less than four cubits one may not. This, then, is the context in which four cubits are mentioned in connection with an aris: when one wishes to plant in the space between the vines and the fence. But for a separation from the vines in the opposite direction, where we are not dealing with the space between the vines and the fence, four cubits are not required, since in the view of Rabbi Yochanan ben Nuri an aris has no status of a vineyard.
The measure of the working area of a vine:
Regarding the view of Rabbi Yochanan ben Nuri, that when there are four cubits one sets aside only the working area, the mishnah clarifies: "Vechamah hi avodas hagefen?" - what is the measure of the working area of a single vine, an individual vine, as opposed to a vineyard? "Shishah tefachim lechol ruach" - six handbreadths in every direction, as has already been explained. Rabbi Akiva disagrees with this measure and holds that three handbreadths suffice as a separation from a single vine, and not six.
In summary: In this mishnah we learned the definition of an aris - five vines alongside a fence ten handbreadths high, or alongside a trench ten handbreadths deep and four handbreadths wide - and the law of four cubits that applies to it. We examined the dispute between Beis Shammai and Beis Hillel as to whether we measure from the roots of the vines or from the fence, and the two ways of understanding which of them is the stricter; and in contrast, the view of Rabbi Yochanan ben Nuri, that an aris has no status of a vineyard, and that the four cubits were stated only with respect to the space between the vines and the fence, in which one sets aside six handbreadths for the working of the vine - and according to Rabbi Akiva, three.
In what follows we will deal at length with the laws of the aris and its details.