Whoever takes hold of ownerless property acquires it. Any objects found naturally in deserts, rivers and streams - e.g., grass, trees, wild fruit and the like - are ownerless. Whoever first takes hold of such an object acquires it.
When a person catches fish in a sea or in a river, and similarly, when he catches fowl, or various wild beasts, since they are ownerless, he acquires them. He may not, however, hunt in a field belonging to a colleague. Nevertheless, if he snares an animal there, he acquires it. If fish - or wild beasts or fowl - are in vivariums belonging to another person, they belong to the owner of the vivarium. A person who snares an animal there is considered to be a robber. This applies even if the vivarium is large and effort is required to snare the animal.
However, when a person takes a fish from the net of a colleague at sea, or takes a beast from a snare of a colleague set in the desert, this is prohibited by virtue of Rabbinic decree. If the snare could be considered to be a container, and the person took the fish or the animal from the container, he is considered to be a robber.
When a person spreads out a snare in a field belonging to a colleague, and traps a beast or a fowl, he acquires it, even though he does not have permission to do this. If the owner of the field was standing in the field at the time the animal was trapped, and said: "My field acquires this on my behalf," the owner of the field acquires it, and the owner of the snare does not acquire anything.
🌿 Hefker Basics
Property declared hefker (ownerless), wildlife, and natural resources belong to whoever takes possession first — but stealing from another's trap is forbidden even when the prey has no owner.
When fish jump into a boat, they become acquired by the owner of the boat, for the boat is considered to be a protected courtyard. It is not considered to be a moving courtyard, because the boat does not move on its own. It is the water that moves it.
🚤 Boat Rule
Fish that jump into a boat are acquired by the boat's owner because the vessel functions as a protected courtyard, automatically transferring ownership.
When a convert dies without having fathered a Jew after his conversion, he has no heirs. Instead, the first person who takes hold of his property acquires it. A neighbor does not have the right to buy the property from the person who took hold of it, because this is considered to be a gift.
The following laws apply when there are two fields in an estate that belong to a convert, with one boundary marker between them. If a person manifests ownership over one of the fields with the intent of acquiring it, he acquires it. If he manifests ownership over it with the intent of acquiring both it and the other field, he acquires the field over which he manifested ownership, but he does not acquire the other field. If he manifests ownership over one field with the intent of acquiring only the other field, he does not acquire either of them. He does not acquire the field over which he did not manifest ownership because he did not manifest ownership over it. He does not acquire the field over which he did manifest ownership because he did not manifest ownership with the intent of acquiring it. If he manifests ownership over one field with the intent of acquiring it, the other field and the boundary marker between them, or if he manifests ownership over the boundary marker with the intent of acquiring both fields, there is an unresolved doubt with regard to the matter. If another person comes and manifests ownership over one of the fields itself with the intent of acquiring it, the latter person becomes the legal owner.
Similarly, when two houses are located one within the other, if a person manifests ownership over one of the houses with the intent of acquiring both it and the other house, he acquires only the house over which he manifested ownership. If he manifests ownership over one house with the intent of acquiring only the other one, he does not acquire even the house over which he did manifest ownership.
When a person takes hold over a deed of sale within the estate of a convert with the intent of acquiring the land mentioned in that deed, he acquires only the document itself. He may use it to wrap around the top of a bottle or the like.
When the boundaries of a field belonging to a deceased convert are clearly marked, when a person plunges a spade into the field in one place, he acquires the entire field. If the boundaries of the field are not clearly marked, by plunging the spade into that one place, he acquires only a portion over which a team of oxen will pass when plowing, before the team returns. A boundary marker and a chatzav used to designate boundaries serve as cut-off points with regard to the estate of a convert. Whoever manifests ownership over the field acquires only up to the boundary marker or the chatzav.
Whatever is considered significant to create a separation with regard to the distribution of pe'ah is also considered significant to create a separation with regard to the acquisition of the property of a deceased convert. What is implied? If there was a stream, an irrigation ditch or the like, the person seeking to acquire the field acquires only up to the stream or up to the irrigation ditch. Whatever creates a distinction with regard to the domains of the Sabbath, creates a distinction with regard to the acquisition of the property of a deceased convert - for example, a situation where a private domain or a carmelit is interposed between two fields. Indeed, a distinction is created, even if the two fields were separated by a domain that is considered a distinction with regard to the transfer of a bill of divorce.
Whenever a distinction is created with regard to the laws of ritual impurity, it also applies with regard to the acquisition of the property of a deceased convert. What is implied? A person enters a valley. There is an object that conveys ritual impurity on one side of the valley, and the person does not know whether or not he has reached the place that is ritually impure. Wherever the person would be considered to be ritually impure is considered to be a separate entity from the field as a whole.
The following law applies when there is a large valley containing many fields, all belonging to one convert, and there is no boundary marker, chatzav or any other entity that creates a distinction between them. If one person comes and manifests ownership over a portion of the valley with the intent of acquiring the entire valley, he acquires all the land that is known to be owned by that convert.
🏡 Convert's Property
When a convert dies without Jewish heirs, his property is ownerless. Acquisition requires a clear, complete act of possession — boundary markers, plowing, or taking a deed all define what is and isn't acquired.
When a gentile sells movable property to a Jew or buys movable property, he acquires and transfers the property through meshichah or through the transfer of funds. Different rules apply with regard to landed property. A gentile does not acquire landed property from a Jew without a deed of sale, nor does he transfer property without a deed of sale. For he will not rely on anything but a deed of sale. For this reason, if a Jew purchased a field from a gentile and paid the money for it, but before he could manifest his ownership over it, another Jew came and manifested ownership over it in a manner similar to that described above with regard to the acquisition of the property of a deceased convert, the latter person acquires the land. He must, however, repay the money to the purchaser. The rationale for the decision is that the gentile abrogates his ownership over the property at the time he receives the money. And yet, the Jew purchasing the land does not acquire it until the deed of sale reaches his hand. In the interim, the property is like property in the desert concerning which the rule is: Whoever manifests ownership over it acquires it.
When does the above apply? When there are no known laws enforced by the governing sovereign. If, however, the law of the governing sovereign and his judgment is that only a person whose name is mentioned in the deed of sale - who paid money for the property or the like - can acquire the land, we follow the law of the governing sovereign. For we rule according to all the financial laws of the governing sovereign.
⚖️ Local Law
When the sovereign's law mandates a specific mode of acquisition (e.g., a written deed), Jewish law follows it — the principle of dina d'malkhuta dina applies to movable property transfers.
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🎓 Key Principles
Chapter 1
🌿
First Possession Wins Ownerless property — whether declared hefker or naturally wild — belongs to whoever takes hold of it first. Speed and clear intent of acquisition are decisive.
🚫
Theft Without Ownership Is Still Theft Taking an animal from someone else's trap — even though the animal is technically ownerless — is prohibited, because the trapper has a prior claim through his tool and effort.
🏡
A Courtyard Acquires for Its Owner A person's guarded courtyard or vessel functions as his legal hand. Items that enter it — like fish jumping into a boat — are automatically acquired without any further act.
⚖️
Partial Possession, Partial Acquisition When acquiring a convert's estate, each field or house must be seized individually. A single act of possession on one parcel does not automatically acquire adjacent parcels — even within the same estate.