Bava Basra, Chapter 3, Mishnah 5. Until now we have dealt with the chazakah of houses and establishing a chazakah of ownership. The principle was that when a dispute arises over the rights to a property, we assume that the rights remain with the original owner - unless the one holding the property claims that he has been dwelling in it for three years, that he has a claim as to why he was entitled to dwell there for the last three years, and that the original owner (mara kamma) did not protest against him.
Chazakah on a Private Property:
Let us illustrate with an example, which we will want to contrast with our Mishnah: A person who sets up a shed in his friend's backyard - this is a usage that people are particular about, and a normal person would protest: "Why on earth would you set up a shed in my courtyard?". If the shed stood there for three years, and now the owner of the courtyard asks to remove it, the squatter comes to beis din and claims: "There was an agreement between us, and he gave me permission to be situated here." He does not have a deed in his possession, and the details of the story do not matter - the main thing is that he has a claim. Beis din will accept his words and ask the owner of the courtyard: If this was not the case, why did you not protest during these three years? In such a case the squatter is believed, since it is not the way of a person to allow his neighbor to set up a shed in his courtyard without permission for three years.
Partners - A Different Law:
Things are different when dealing with partners, and this is the context of our Mishnah. Two neighbors who have a shared courtyard, and the entrances of their houses open to it, share it equally. The meaning of the term 'partner' in halachah is that both partners have rights in the entire thing: the whole courtyard is mine and the whole courtyard is yours, and my children are permitted to play anywhere in the courtyard, and so are the children of my partner.
Let us assume now that one of the partners parks his bicycle in a certain spot in the courtyard, thereby preventing his friend's children from playing in that spot, and the bicycle stands there for years. When the second partner asks to move it, the first will answer him: "I have a right to stand here. The bicycle has been here for three years and you never said a word." Now, beis din will not say in such a case that a normal person would protest, and that the lack of protest for three years proves agreement. Since both are entitled to use the courtyard, leaving the bicycle over a long period of time does not prove anything: The second partner says in his heart that whenever he needs the space he will ask his friend to move the bicycle, since it is not a permanent fixture. It is true that it stood there for many years, but now he has changed his mind.
It turns out that with a non-permanent fixture the partner is not expected to protest his friend's use, since both are allowed to use the courtyard. Therefore, the claim raised in beis din, that he did not protest for three years, proves nothing, because it is not the way of a partner to be particular about this.
Temporary Usage versus a Permanent Structure:
Our Mishnah distinguishes between two types of usage: temporary usage - like a bicycle that stood in its place for many years, and can be moved to the other side of the courtyard with the flick of a finger; and permanent usage - such as a permanent shed that one of the partners built to store his bicycle, which is attached to the ground and forms part of the courtyard. Such a structure does not move with a flick of a finger, and in such a case the partner will indeed protest his friend's permanent takeover of the courtyard; and if he did not protest, his silence serves as testimony to his agreement.
A Dispute Among the Rishonim Regarding the Parameters of Chazakah of Partners:
The Approach of the Bartenura (who follows the approach of Tosafos and our other Ashkenazi Rabbis, and the Rema rules accordingly) - The law of partners is exactly like the law of chazakah of houses. The mere setting up of the shed does not acquire ownership, and a claim of right is also required. The three years of a lack of protest over the shed in the shared courtyard serve as proof to his claim that the second partner gave him permission to use this space. He does not acquire the right of usage merely by virtue of the squatting, rather he must claim: I am entitled to the space in the courtyard because you gave me permission; and the proof - I have no other proof in my possession besides the fact that the structure stood for three years, and a normal person would protest within three years, and this one did not protest.
The Approach of the Rambam (and the Mechaber rules accordingly) - Partnership is a good thing, but good fences make good neighbors, and one partner does not set the rules on his own. If one partner set up a large shed to store his bicycle in the shared courtyard, which is supposed to belong to both of them, and the shed stands there permanently - the second partner will protest immediately, and will not pass over it in silence for a long time. Since he did not protest immediately, it is an agreement. Therefore there is no law of three years at all here regarding establishing a chazakah with partners. Furthermore: There is not merely proof here that he was given official permission, but rather the second partner waives his rights, and by virtue of this waiver the builder of the shed is entitled to be situated there. This waiver takes effect immediately; there is a discussion about how fast is considered 'immediately', but in any event we are talking about a short time, and certainly not three years.
According to the Rambam, therefore, when one of the partners sets up a permanent structure that cannot be moved easily and the second partner does not protest, the first acquires the rights permanently. To clarify matters: In both approaches, even after the partner acquired the right to leave his shed, they were partners until that moment. That is, if there are a hundred square feet in the courtyard, and they rent it to someone else or sell it - they will divide the proceeds equally. However, if they come to divide the courtyard, the owner of the shed will receive only fifty square feet, but within them he will receive specifically the portion that he held, since he will claim that he was entitled to it - whether according to the Bartenura, that there was an explicit agreement there, or whether according to the Rambam, that the partner agreed in silence and thereby waived his rights.
This is the essence of our Mishnah: a division between two types of things - temporary uses, which can be changed quickly and easily, and permanent uses, which cannot be changed quickly and easily, and to which a person would more readily object, whether immediately or within three years according to the opinion of Rabbeinu Tam.
The language of the Mishnah:
The Mishnah opens: "Eilu devarim sheyesh lahem chazakah ve'eilu devarim she'ein lahem chazakah" - these are things that have a chazakah and these are things that do not have a chazakah. It brings examples of uses of shared property that create a chazakah or do not create a chazakah - meaning, that the absence of a protest for three years, according to the opinion of the Bartenura, is proof of his right to remain there.
The temporary things, which do not have a chazakah:
"Hama'amid behemah bechatzer" - keeping his animal in the courtyard.
"Tannur vekirayim" - an oven or a stove that is not fixed to the ground; like a barbecue grill that can be rolled and moved to another place in the courtyard.
"Vereichayim" - a hand mill, which can be moved from place to place very easily, and is not fixed to the ground like a permanent millstone.
"Umegadel tarnegolim" - chickens running around in the courtyard.
"Venatan zivlo bechatzer" - a pile of manure that he keeps in the courtyard for fertilization.
Regarding all of these it is said "einah chazakah" - they do not create a chazakah, because on the part of the partner it is not unreasonable to say: "Leave your chickens here as you wish, until I need the space." This can go on for years, and it does not involve a formal waiver of anything.
"Aval" - The permanent things, which have a chazakah:
The following things are permanent structures to which a normal partner would object, and therefore they can create a chazakah that grants the partner the right to remain there:
"Aval asah mechitzah lebehemto gevohah asarah tefachim" - he does not merely stand an animal in the courtyard, but rather builds a pen surrounded by a partition ten tefachim high, and this is a permanent pen.
"Vechen letannur vechen lekirayim" - that he made an enclosure for them, or fixed them in concrete to the ground.
"Vechen lereichayim" - a large, formal grinding mill, fixed to the ground, and not a portable hand mill.
"Vechen shehichnis tarnegolin letoch habayit" - a shared area inside the house, where one partner allowed his friend to bring in chickens. Chickens dirty wherever they go and do their business in every corner, and no normal person would pass over this in silence unless he had given his consent - and this point is worth considering.
"Ve'asah makom lezivlo amok sheloshah vegavoha sheloshah" - a designated place in the shared courtyard for keeping manure, where the manure is not piled up casually, but a special place was prepared for it: a pit three tefachim deep in the courtyard, or a platform raised three tefachim - a built place designated for the purpose of storing manure.
Regarding all of these - "harei zu chazakah": all of these things are considered to establish a chazakah, because they are the type of things that constitute permanent and formal structures, to which a partner would usually object unless they were acceptable to him.