Gemara

(Mishnah): A case occurred in which one rented a bathhouse 'for 12 Dinarim for the year, a Dinar per month' (and it became a leap year). R. Shimon ben Gamliel and R. Yosi ruled that he pays half for the added month.

(Rav): I would have ruled that he must pay for the entire month.

He holds that when one says two contradictory clauses, we follow the latter.

(Shmuel): The Mishnah discusses when they come to Beis Din (for a ruling) in the middle of the 13th month, but if Levi said at the beginning of the month 'you must pay extra for this month', Yehudah must pay for the entire month. If Levi made no claim until the end of the month, Yehudah need not pay.

Shmuel is unsure whether or not the latter phrase is binding, so we follow Chazakah. Levi is Muchzak in his bathhouse. Yehudah cannot use it without proving that he is entitled to. Yehudah is Muchzak in his money; Levi cannot make him pay for what he used of the extra month.

(Rav Nachman): The owner is Muchzak in his land.

He is unsure which phrase we follow. Even if the phrase favoring the renter was said last, the owner is Muchzak and the renter must pay.

110a: If a document does not specify for how many years a lender (Reuven) will eat the Peros of Mashkanta (land given for collateral), and he already ate the Peros for three years, the question is about the Peros, which are with Reuven. The Chazakah favors him, so he need not pay.

Question: The Halachah follows Rav Nachman (in monetary laws), who says that when in doubt, we apply Chazakah to the land and say that it belongs to the original owner!

Answer: That is when the doubt will never be resolved. Here, witnesses might come and testify how many years it was for. Beis Din does not make one pay if future testimony might force Beis Din to retract its ruling.

Rishonim

Rif: Rav Nachman said that even if they ask at the end of the month, the owner is paid. This is not because we follow the latter clause. It is even if he rented 'for a Dinar per month, 12 Dinarim for the year'! Rather, he holds that land is in the owner's Chazakah. We do not take it from him without a proof.

Rif (Bava Metzia 59b): The Halachah follows Rav Nachman.

Rosh (Bava Metzia 8:30): Regarding land, the Halachah follows Rav Nachman, that land is in the owner's Chazakah. This is only if the matter is not prone to become known, like in the coming Perek (110a).

Hagahos Ashri (citing Or Zaru'a): If one rented a house until Adar, and they argue about whether this is Adar Rishon or Sheni, they divide (Adar Sheni).

Shach (CM 312:15): The Or Zaru'a learns from a Tosefta (Bava Metzia 8:14). I say that the Tosefta is like R. Shimon ben Gamliel and R. Yosi, who do not follow Chazakah of the land. The Halachah is not like them, rather, it is like Rav Nachman! The Or Zaru'a rules like the Rosh (Bava Metzia 2:8) said in his name, that when a judge cannot know, because the Gemara never resolved the Halachah, we divide. Rav Nachman follows Chazakah only regarding contradictory clauses, for we cannot know his intent. Regarding Adar, the Safek is not about the words, rather, we do not know which Adar is primary. R. Meir and R. Yehudah argue about this in Nedarim (63a), and Poskim argue about whom the Halachah follows. Therefore, we divide. We (unlike the Or Zaru'a) rule that when there is a Safek about the Halachah, ha'Motzi mi'Chavero Alav ha'Re'ayah, so we follow the Chazakah of the land.

Rambam (Hilchos Sechirus 7:2): If one rented a bathhouse for a year, and it became a leap year, the tenant gets the added month. If he rented it by the month, the owner gets the added month. If when discussing the rental he mentioned both 'months' and 'year', no matter which he mentioned last, the owner gets the added month. Land is in the owner's Chazakah. We do not take it from him without a clear proof. The same applies if a Ba'al ha'Bayis says 'I rented (the house) to you for this period of time', and the tenant says 'I rented Stam', or 'I rented for a longer period', the tenant must bring a proof. If he does not, the owner swears Heses and evicts him.

Magid Mishneh: The Rashba says that this is only if he said 'this year', or 'the year', which like saying 'this year', but if he said 'one year', it is only 12 months, like most years. In Nedarim (63a) the Rashba says that this is only when he stipulated on Rosh Hashanah. However, if it was in the middle of the year, and he said 'the year' or 'this year', he gets only until Rosh Hashanah! If he said 'one year', he gets only 12 months, even if he said 'from today.' The Rambam (Hilchos Nedarim 10:4) disagrees. He says that one who vowed for a year is forbidden in the added month. The Mishnah in Bava Metzia favors the Rambam. The same applies to every case of land that is not prone to be clarified.

Ran (Nedarim 63a DH Masnisin): The Rashba learns from Erchin 31a, which says that we include the added month (in the year to redeem a house sold in a walled city) only because the Torah said "a full year."

Rejection (of Rashba - Ran, ibid.): If he gets 13 months only if he stipulated on Rosh Hashanah, the Gemara should have taught this! The Gemara taught Stam that the tenant gets the added month. We cannot say that this is only in a rare case! There is no proof from Erchin, for there they did not stipulate. One might have thought that the Torah gives redemption rights only for 12 months, like most years.

Beis Yosef (CM 312 DH u'Mah she'Omar b'Shem): The Ran and Magid Mishneh did not see Teshuvas ha'Rashba, in which he argues only l'Halachah, but in practice, he defers to his Rebbeyim and the Rambam.

SMA (312:23): Why did the Tur bring the Rashba? The Rashba said so only l'Halachah! Also, regarding Nedarim, the Tur says that if in the middle of the year he said 'this year', he is forbidden until Rosh Hashanah, but if he said 'one year' or (Stam) 'a year', he is forbidden for a full year from day to day! The Rashba learns from money to Isurim and vice-versa! I resolve as follows. Here the Tur discusses one who, on Rosh Hashanah, says 'one year' or (Stam) 'a year'. Surely, he intends to exclude the added month. Had he wanted to include it, he would have said 'this year'! Rather, he shows that he refers to a Stam year, which is usually 12 months. Regarding Nedarim, the Tur discusses who, in the middle of the year, says 'one year' or 'a year'. He means 13 months (if there will be an added month). He could not have said 'this year', for this would connote only until Rosh Hashanah. The Ran does not distinguish this way, but the Tur does.

Poskim

Shulchan Aruch (CM 312:15): If one rented a bathhouse for a year for a certain sum, and it became a leap year, the tenant gets the added month. If he rented it by the month, the owner gets the added month. If he mentioned both 'months' and 'year', whether he said 'one per month, 12 for the year', or vice-versa, the owner gets the added month, for land is in the owner's Chazakah.

Beis Yosef (DH DH u'Mah she'Omar Hizkir): Rashi says that even if he comes at the end of the month, the owner gets it, for the Safek arose at the beginning of the month, and we establish the land in the owner's Reshus. The tenant lived in another's Reshus, therefore, he must pay.

SMA (25): The Nimukei Yosef says that the Safek is when both clauses were adjacent to each other. If they were separate, surely we follow the latter clause, like regarding loan documents.

SMA (26): Regarding such a Safek about Metaltelim, if one seized them, we do not take them from him

Shach (14): Regarding a Kohen who seized a Safek Bechor, and contradictory pairs of witnesses, the Rosh (Bava Metzia 1:13, Bechoros 2:13) says that if the tenant has a Vadai claim, e.g. you explicitly said that it will be 12 for the year even if it is a leap year, we do not take from him. In Bava Metzia 100a and CM 317:3, we say that even when a lender has a Vadai claim, we take from him because the land is in the borrower's Chazakah. There is different, for we know how much he ate, just he claims that he rented it for three years. Therefore, we follow the Chazakah of the land. It is as if the Peros are in the borrower's Reshus. Here, if the tenant claims that the stipulation was to pay only 12, we are unsure if the Peros are 12 or 13. Chazakah of the land does not resolve this. Therefore, the Rosh derived that seizure does not help for a Safek. In Bava Metzia we asked from Rav Nachman, wno holds that Chazakah of land helps for a Safek; it is as if the Peros are in the Reshus of the landowner. If so, for the same reason a borrower should collect Peros from a lender even if the lender is Vadai. The Rosh says that seizure helps only with a Vadai claim. This refers to seizure without Reshus. If he was allowed to seize, it helps even with a Safek claim.

Rema: However, if one hired a teacher for he said son and said such expressions, and he taught him in the added month, the father need not pay for it.

Gra (27): Rav Nachman said only that land is in the owner's Reshus. The teacher shows that he taught in the added month due to the contract, for he did not ask the father. Also, if one taught David's son without David's Da'as, this is not called benefiting him regarding vows, therefore, David need not pay him.