Gemara

12b: Reuven bought land bordering his father's land. His father died, and Reuven requested the portion bordering the land he bought.

(Rabah): In a case like this, Kofin Al Midas Sedom (we force one to benefit others (in this case, Reuven) if he himself will not lose).

Objection (Rav Yosef): His brothers can say 'that land is (worth more,) like Bar Meryon's land.'

The Halachah follows Rav Yosef.

(Rabah): If there are two fields, and each borders on a river, Kofin Al Midas Sedom.

Objection (Rav Yosef): Perhaps one river will dry up! Shimon can demand half of each field.

The Halachah follows Rav Yosef.

(Rav Yosef): If both fields border on the same river, Kofin Al Midas Sedom.

Question (Abaye): Shimon can say 'I prefer (that your fields be disconnected, so you will need) more sharecroppers' (so my property will be guarded better)!'

The Halachah follows Rav Yosef. We do not honor such a request.

Rishonim

The Rif (8a) brings our Gemara.

Rambam (Hilchos Shechenim 12:1): If brothers or partners came to divide a field, and it was all the same quality, and Reuven said 'give to me my share near the other field that I own, so I will have a connected field', we heed him. It would be Midas Sedom for the other to refuse. However, if one portion was better or closer to the river or the road than the other, and they evaluated its value above the others, and he asked to receive it, we do not heed him. Rather, they divide through a lottery. If he said 'give to me half the area on the bad side near my field without compensation, and you take the good half', some Ge'onim say that we heed him. I agree.

Rosh (1:46): If Reuven requested to inherit his share of his father's property bordering land that he previously bought, Rav Yosef said 'the brothers can say 'that land is like Bar Meryon's land.'' Rashi explains that it was Sedeh ha'Ba'al (rain suffices for it). Sometimes, one such field prospers more than another. Rashi said so, for later Rav Yosef needed to give a different reason (perhaps the river will dry up). Rashi concluded that all irrigated fields are the same, but one Sedeh ha'Ba'al can prosper more than another, e.g. the rain flows from one to the other. This is difficult, for also regarding irrigated fields, sometimes the crops in one field are blasted, and another field is not stricken! R. Tam explains that they can evaluate the property like land of Bnei Meryon, who were rich and sold only for a high price. This is not Midas Sedom, for if the lottery will award the adjacent field to the other brothers, they may say 'we will trade with you only for great compensation.' Also before the lottery, they need not pardon their opportunity to get the adjacent field. Rabah says that we force due to Midas Sedom, since the adjacent field is worth more only (to Reuven,) because it borders Reuven's field. The Halachah follows Rav Yosef. R. Yonah says that if the brothers claim an inflated value for the adjacent field, if Reuven is clever, he will decrease from their price and say 'I will take it for this price, or you will.' They will not want to do so, and he will get it for a slightly higher price. Accepting a field for more always overrides division through lottery. When brothers come to divide through lottery, one can say 'I will pay extra for this share. You may have it for this price, or I will take it for this price, without a lottery.' The Ra'avad agrees, for all gain through this. Some explain 'they evaluate like Bar Meryon's property' in this way. They do not intend to pay the extra, just to make Reuven pay extra. I say that 'Iluy' (added estimation) refers to inflating the price without reason, just because the portion is dear to him.

Rosh (47): R. Tam explains that the case of two fields, each of which borders on a river, does not refer to when Reuven owns an adjacent field. Rather, Shimon and Levi come to divide two fields. Shimon wants to get half of each field, and Levi wants one entire field. Rabah says that it is Midas Sedom not give an entire field to each, assuming that both are the same quality. Rav Yosef disagrees, for perhaps one river will dry up. (Shimon wants security that he will have some fertile land.) Inflating the price does not apply here, for neither owns an adjacent field.

Rosh (ibid): When both fields border on the same river, Rav Yosef says that Kofin Al Midas Sedom. Abaye said that one can say 'I prefer to increase sharecroppers; the Halachah does not follow him. R. Yonah derives that Rav Yosef needed to mention Midas Sedom. The primary law of division is not that each gets a whole field. Rather, each gets half of each. Abaye says that he can say that he wants more sharecroppers, because the primary law of division is to split each field; it is not Midas Sedom to demand this, because he benefits through this. If the primary law of division were that each gets a whole field, Abaye would not say that he can demand two halves to increase sharecroppers!

Hagahos Maimoniyos (Sof Sefer Kinyan, Teshuvah 37): According to Rashi, if they divide houses, we cannot say that one house will prosper more than another, so Reuven receives near his property. It is a Safek whether the Halachah follows Rashi or R. Tam, so Reuven cannot force them to give him a share near his property.

Poskim

Shulchan Aruch (174:1): If brothers or partners came to divide a field, and it was all the same quality, and one of them said 'give to me my share near the other field that I own', so I will have a connected field, we heed him. It would be Midas Sedom for the other to refuse.

Beis Yosef (DH V'Chosav Rabeinu): Teshuvas ha'Rosh (96:2) prefers Rashi's explanation. According to R. Tam, Rabah is more reasonable (the Halachah should follow him)! Since the only reason he wants the other field is to force Reuven to pay more, this is Midas Sedom. If not, why do we ever force due to Midas Sedom? He loses money that he could demand from the other to allow him to benefit! Rather, in such cases we force. Also, the Sugya connotes like Rashi. When it says 'if each field borders a river...', this connotes that we refer to what was discussed above. Even though an irrigated field can be blasted, it is rare that one is blasted more than another. It is common for rain to descend to one part of the field, and it prospers more than the other half. Also my Rebbi says so.

Beis Yosef (DH v'Chosav): The Rambam rules like Rabah! It seems that the Rambam holds like the Ramban and Rosh say in the name of Ge'onim, that 'inflating the price like Bar Meryon's land' means 'accept this increased price, or let us have it for this.' Rav Yosef argues only when he inflates the price. However, the Rambam does not discuss this. Rather, he holds that whenever the lands are equal, all agree that Kofin Al Midas Sedom to give Reuven near his land. Rav Yosef argued only in a case of two rivers, when there is a reason to object. We do not know that land on one river is better than the other, but it is plausible, so we are concerned for it. However, if the case of two rivers explains the previous case, why did the Gemara need to rule like Rav Yosef in both cases? Perhaps after it ruled like Rav Yosef, it explained that this is when the fields are on two rivers, for if not, Rav Yosef agrees. Or, in the Rambam's text, the Gemara rules like Rav Yosef only once. We can say that his text rules like Rav Yosef only regarding two rivers. When they border on one river, this is like equal lands, and the Halachah follows Rabah, even though it is possible that one of them will be more fertile than the other.

Rema: Some say that we do not force him. Rather, he must inflate the price until his partners consent.

Gra (4): This is like R. Tam.

Rema: Some say that it is a Safek, and Kol d'Alim Gevar (whoever overpowers will take it).

Shach (2): First they make a lottery. If Reuven gets near his field, this is fine. If not, Shimon did not yet merit the adjacent field. Rather, Kol d'Alim Gevar, for perhaps the Halachah follows Rashi.

Shulchan Aruch (ibid): However, if one portion was better or closer to the river or the road than the other, and they evaluated its value above the others, and he asked to receive his estimation, we do not heed him. Rather, they divide through a lottery. If he said 'give to me half the area on the bad side near my field (without compensation), and you take the good half', we heed him.

SMA (7): When it says '(he requested) his estimation', this means his portion. The Rambam says that one can refuse to take a gift, for "one who hates gifts will live." If so, he should be able to say 'I do not want the good half for free, nor can I pay for it!' However, here it is not called a gift, for his partner prefers the bad half because it is close to his other field.