The mishna in Kiddushin (26) lists the three ways in which a person may acquire land. In the case of portable items, physically demonstrative actions displaying the transfer of ownership may be performed. As land cannot be moved or lifted, abstract acts must substitute as an act of kinyan. The mishna lists money (depositing money in the hands of the seller), shetar (issuing a deed of sale) and chazaka (to be described in this shiur) as the three available options. Though the first two examples seem self-evident, the nature of the kinyan known as chazaka remains less obvious. The next two shiurim will explore the manner in which this ma'aseh kinyan operates.
A complementary mishna in Bava Batra (42) lists the various forms of the act of chazaka. According to the mishna, the buyer should either "lock, fence in, or break the fence surrounding the land he wishes to obtain." Apparently, all these acts are meant to establish some form of abstract hold upon a piece of land. A buyer of a portable item takes actual, physical possession through the performance of a ma'aseh kinyan. He lifts a watch (hagbaha), pulls an animal into his home (meshikha), or receives the reins of a large animal or boat (mesira). In each instance, the act affirms his ownership as it grants him physical control over the item. As land doesn't allow such palpable possession, a substitute is found in the form of chazaka. By changing the nature of the field, either by locking or unlocking, a person establishes his CONTROL over the land and thereby establishes his status as owner. From this standpoint, chazaka constitutes a physical act of control over the land and functions similarly to the manner that meshikha or hagbaha would in the case of portable items.
An interesting discussion between Rashbam and Tosafot possibly reflects a different view of chazaka. The Rashbam in Bava Batra (53a) claims that simply locking a door would be insufficient. When the mishna mentioned locking as a form of chazaka, it referred to the actual installation of a lock. The connotations of the Rashbam's position are clear. It is not sufficient to merely perform an act upon the land. Rather, the buyer must contribute some tangible addition to the property. Nothing new is added by merely locking a door. By installing a lock, however, the buyer alters the property and can thus be considered as having established his control over it.
Tosafot in Bava Batra argue with the Rashbam and view the closing of a preexisting lock as sufficient for chazaka. As they conclude, as long as a person performs an act which indicates or announces his position as ba'al ("muchach milta shehabayit shelo"), the chazaka is successful. Possibly, Tosafot disagree with the aforementioned definition of chazaka. Were chazaka an attempt to dominate the land by changing it, they might concede that a palpable change is necessary. Since, however, chazaka is merely an attempt to declare status over the field, anything which displays ownership suffices. Regarding portable items (which are indistinguishable and can be relocated from place to place), a person cannot acquire ownership by merely exhibiting his status. Land, however, is immobile and distinct. Acquiring ownership demands simply publicizing that status to others.
A second issue which might be impacted by this question surrounds the case of "mavriach ari." The gemara claims that providing benefit to the field by preventing damage is not considered a legitimate act of chazaka. For example, if water threatened to swamp the land and the buyer placed a rock in the wall preventing the water from entering, no chazaka has been performed. The Yad Rama explains this rule in accordance with our first view of chazaka. Preventing damage is not considered an addition to land. For example, a landowner is not obligated to compensate someone for preventing damage to his land, though he must reimburse someone who performed capital improvement (building a house, landscaping, etc.). Similarly, preventing water from entering the field of another does not add anything new to the field and thus does not constitute an act of chazaka. This explanation of "mavriach ari" echoes the earlier position, that chazaka demands some form of creative addition to the land.
The Ri Migash (and, consequently, many Chakhmei Sefarad) interpret the gemara differently. As the person saving the field from water damage is acting upon a mitzva to protect other people's property, this cannot serve as chazaka. The act of chazaka must be discernable and exclusive. Any action taken for some other primary, motivating purpose cannot also serve as chazaka. This perspective seems to coincide with the second view of chazaka (the one suggested by Tosafot). If chazaka is meant to declare ownership, the buyer must act as new owner by performing one of the prescribed acts. If the act is taken for some other purpose, no display of ownership has been executed. If chazaka were to be understood not as a public exhibition of ownership but as some sort of 'physical domination' of the land by changing it, it might matter little why the change was introduced.
Yet another factor possibly revolving around the fundamental nature of chazaka relates to the quality of act which must be performed. The gemara in Bava Batra (53a) originally depicts the chazaka of 'gadar' (building a wall) as building to a height of ten tefachim (the standard halakhic shiur for walls with regard to shabbat, Sukka, kilayim, etc.). Subsequently, the gemara suggests that as long as a meaningful addition to the wall was made, the chazaka has been accomplished. If the addition prevents people from entering the land (while prior to the chazaka they had free access), chazaka exists and the buyer achieves ownership. The Rishonim differ as to whether or not the gemara actually intends to suspend the ten tefachim requirement discussed earlier. According to the Rashbam, the gemara rejects the ten tefach condition, and chazaka exists as long as the new wall prevents trespassers. The Yad Rama argues that even though the new wall effectively protects the field, if the height doesn't reach ten tefachim, the chazaka is unsuccessful. Possibly, these two positions reflect the two above stated versions of chazaka. According to the Yad Rama (consistent with his earlier definition of mavriach ari), chazaka entails dominating the field by changing it or adding something new. Without building a halakhic wall, no legal addition has been rendered. By contrast, the Rashbam might maintain that chazaka is only intended as a display of ownership. As long as the buyer has raised the wall to a level which prevents trespassers, he has demonstrated his status as owner of the field.
(NOTE: This assumption - that the Rashbam views chazaka as a display and not as dominance - must be compared with the earlier stated position of the Rashbam, that locking a door is insufficient and that na'al can be accomplished only installing a lock. From that statement of the Rashbam, it appears that chazaka indeed involves dominance.)
A final question seemingly based on the nature of chazaka might be the scenario of closing a door and subsequently opening it. Assuming locking a door constitutes chazaka (as opposed to the Rashbam's view which requires the installation of a lock), what would happen if the buyer, after locking, immediately opened it? The Rambam (Hilkhot Mekhira perek 1 halakha 10) actually describes chazaka as closing and opening (this is based on a gemara in Gittin 77b, which portrays chazaka in this manner). The Ramban, in his commentary to Bava Batra, questions the efficacy of closing a door which is opened just a few moments later, as the condition achieved by the closing is canceled by the opening. If, however, we define chazaka as a public display of ownership, opening a door after it has been closed might enhance the display. Only an owner has absolute control expressed by the ability to freely open and close a door. Had chazaka been the attempt to change a field by adding some component to it, the removal of that component immediately after its addition would not qualify as a chazaka.