Siman 142

Even though there is no chazakah in less than three years, nevertheless, if the possessor brought witnesses that the challenger performed significant acts indicating that he sold it to him—for example, that the challenger lifted a basket of fruit from this field onto the shoulder of the possessor in order to carry them to the house of the possessor, and the challenger knew that the possessor was carrying them to his house for himself; or that he assisted him in gathering the fruit and lifted them from the ground and placed them into the vessels of the possessor, and knew that he would carry them to his house; and all the more so if the challenger himself carried the fruit to the house of the possessor—it is a chazakah immediately. For if he had not sold it to him, he would not have done these things for him. And some say that the same applies if the possessor sent a gift to the challenger from the fruit of this field and he accepted them from him, it is also a chazakah immediately; for if the land were his, he should not have accepted them as a gift, but rather he should have taken everything. And all this is when there are witnesses, for then he is not believed to give any excuse, except when he claims "I brought him down for the fruit," as will be explained, because it is a near certainty that he sold it. But if there are no witnesses, but rather the challenger himself admitted to one of these things that he did and gives an excuse for it, "the mouth that prohibited is the mouth that permitted," and he is believed; for this is not an actual admission, only that in the presence of witnesses we do not accept an excuse [Netivot HaMishpat].

All of this is if the challenger claims that he did not sell him at all, neither the body of the field nor the produce, for then he is not believed. However, if he claims that he sold him the produce for several years, and "I lowered him into this field for the produce, but the body of the field I did not sell him," he is believed and there is no chazakah in this. But when he does not claim so, he is not believed with a migo that he could have said "I lowered him into it for the produce," for this is not a migo, since he desires to extract from him the produce as well, and how could he admit to them? Furthermore, it would be like a migo in the place of witnesses, for in any event it is known from the witnesses that his claim is a lie. Therefore, if one sells to his fellow the produce of his field for several years, he must make a machah every three years to make known that he lowered him into it for the produce, so that after three years he will not be believed even with this claim. Therefore, it is necessary to make a machah or to receive from him a shtar that he only has produce for such and such years.

And so, if Reuven contests Shimon regarding the land between his house and Shimon's house, claiming that Shimon stole it from him, and afterwards Shimon erected a wall between himself and Reuven and Reuven assisted him in its erection, he can no longer contest it, and Shimon acquires a chazakah immediately even before three years. And even if there are no witnesses to this but only the admission of Reuven, it is a complete admission that the land belongs to Shimon, for if it were not so, he would not have assisted him in erecting a wall there. And so, even if there was no contest between them at all, and even if the wall between them stood on the boundary line and the wall between them fell and Shimon built the wall and brought it into Reuven's border, and Reuven assisted him in its building and Reuven knew that Shimon brought it into his own, it is a chazakah immediately, and we say that he waived the land to him, for if it were not so, he would not have assisted him. And not only that, but even if Shimon himself did not know and did not sense at all that he brought it into Reuven's border, nevertheless, since Reuven knew and assisted him, Shimon acquires it immediately by reason of mechilah. And even though he did not intend to acquire it, he acquires it, for only regarding the property of a convert do we require intention to acquire, as I wrote in siman 275, but in a place where there is another mind that transfers it to him, one does not require intention [Nimukei Yosef, chapter 3 of Bava Batra]. And specifically when Reuven admits that he knew that he brought it into his own; but if he says that he erred and did not sense it because he did not recognize the place where the wall stood, if Shimon also says that he did not sense it, Reuven is believed without an oath [it appears to me], for since Shimon also says that it was in error, why should we not believe Reuven? And mechilah in error is not mechilah, even if many years passed and he did not remove it, since it is known that its initial standing was in error. But if Shimon says that both of them knew of this and Reuven gave it to him as a gift or that he purchased it from him, if there are witnesses that he assisted in its building, Shimon is believed with a shevuat hesset that he sold it or gave it to him, and he acquires it immediately and does not need a chazakah of three years. And if there are no witnesses but Reuven admits on his own that he assisted him and that it was in error, Reuven is believed with a shevuat hesset before three years [it appears to me]. And so, if Reuven did not assist at all in the building of the wall, even though he knew that Shimon brought it into his own, Shimon does not have a chazakah before three years. And if Shimon claims that Reuven sold it to him or gave it to him and Reuven denies it, Reuven swears a shevuat hesset and restores the wall to its original place, since it is still before the years of chazakah. And this is specifically regarding the building of a wall, but regarding the opening of a window into the courtyard of his fellow, such as where Shimon opened a window into the courtyard of Reuven, according to the opinion of the Rambam, of blessed memory, since Reuven knew of the opening of the window and did not protest immediately, even if he did not assist him in its opening [Shach], he cannot return and contest it, for regarding damage of sight there is a chazakah immediately. For specifically regarding a wall, it is something he can tolerate and he thinks in his heart: "I will not let him acquire it and I will restore it to its original place," and therefore when he did not assist him, he requires the years of chazakah; but regarding damage of sight, no man can tolerate it, and since he was silent, he certainly waived it. And there are some of our teachers who disagree on this and hold that, on the contrary, regarding a window, even if he assisted him in its opening, he has no chazakah, for specifically regarding the erection of a wall where he encroached upon his land boundary, it is not the way of the world to assist him in this; but regarding the opening of a window where he did not encroach upon his boundary, it can be said that he does not care what he does now in his own property, and he relies on the fact that whenever he wishes, he will block the window for him. And the principles of these laws will be explained in siman 154 with the help of Heaven.

From what has been explained, that when the claimant does something for the possessor from which an admission is apparent, he can no longer claim, our teacher, the Rema, wrote that from this one may learn regarding Reuven and Shimon who have a dispute over the chazakah of residency, and Reuven purchased the chazakah from Shimon for a year, behold the residency belongs to Shimon, and it is like an admission from him; for if the chazakah belonged to Reuven, he would not have purchased it from Shimon for a year. For even though a person may buy his legal rights and does not wish to stand in dispute, nevertheless, this is only if he were purchasing the right from him forever. But when he purchased for a year, behold he has done nothing, for after the year the dispute will be as before; and if so, why did he do this? Rather, it is certain that he admitted to him. And so too if he rented it from him every year for such and such an amount, even if he rented it forever, nevertheless it is like an admission from him, for it is the way of people to purchase and pay money once in order not to stand in dispute, but not to rent [Sma and Netivot HaMishpat] to pay every year and for the name of the lessor to be called upon it. And the same law applies to anything similar to this. However, this is certain: if the beit din sees that Reuven was forced to purchase from Shimon for a year or to rent it because of some necessity that he had, such as if he had no place to dwell or for one of his relatives and other similar necessities, then this is not an admission from him, and everything is according to the matter [it appears to me].