Explanation: Rabeinu Tam explains that our "Dyo" -- "ink" is in fact "Dyo," not the type of ink made out of gallnuts.

Proof#1: That ink is not called "Dyo." This is evident from the fact that Rebbi Chanina taught that if the Get was written with rainwater and a type of gallnuts it is kosher. This implies that this is not "Dyo," as he clearly only discussed things not mentioned in the Mishnah.

Proof #2: Later, when the Gemara asks on Rebbi Avahu who said that one could use rainwater that had some crushed gallnuts soaking in them (so the witnesses could sign over these lines) from Rebbi Chanina, why didn't it ask from the Dyo of our Mishnah?

Proof#3: Additionally, a Sefer Torah requires Dyo, as we said in Shabbos (103b) that if someone write a Sefer Torah without Dyo it should be put in Genizah. This is clearly talking about a Sefer Torah, as is implied in Menachos (31b). How could we write with Dyo of gallnuts on the parchment of a Sefer Torah which is treated with gallnuts? One cannot write with gallnut water (ink) on top of gallnut water (as this is not considered writing)!

Proof#4: Additionally, Rabeinu Tam deduces from the Gemara in Nidah (20a) which states that Rebbi Ami would cut off a piece of black Dyo in order to check a black color of blood. This is clearly our Dyo that is dry, and it is possible to say about it that he chopped a piece off.

Implied Question: The Gemara in Shabbos (23a) states that all types of "Sraf" are good for Dyo, and the "Sraf" of balsam is the best. (Note: It would seem that Sraf refers to the gummy substance put into Dyo made out of gallnuts. This seems to indicate that Dyo is ink made from gallnuts!)

Answer: The "Sraf" mentioned there is not a gummy substance, as it is only normal to put rubber in the Dyo made out of gallnuts.

Rather, Rabeinu Tam explains, Sraf refers to the sap of the bark that our Dyo is made from. This is like the (use of the word Sraf in the) expression "This one's sap is common," in Nidah (10b), used to describe the wet (menstrual) blood of a woman. Similarly, the Gemara in Pesachim (39a) says that a bitter herb has Sraf. A vegetable does not have a gummy substance, but it does have wetness. (Note: All of the above show that the Gemara in Shabbos (23a) is discussing our Dyo.)

Due to all of the above, Rabeinu Tam forbade people to write a Sefer Torah with gallnut ink.

The Gemara's implication in Shabbos (115b) that all Sefarim do not require Dyo besides a Megilah (unlike Rabeinu Tam's ruling above) is something I have explained in (Tosfos in) Shabbos (ibid.).

Explanation: Rashi explains both "Kankantum" and "Shichor" stated in the Beraisa as being "Adriment" (something that causes a black color).

Question: This does not seem correct, as the Beraisa only states things that are not stated in the Mishnah.

Opinion: The Ri says that "Shichor" is "Adriment," and "Kankantum" is, as Rabeinu Shmuel explained in Eiruvin (13a), green ground that is called "Vidroil," or as the Aruch calls it "Vitriolu."

Rabeinu Tam also stated regarding a Sefer Torah that was being fixed, that it is permitted to put "Adriment" in the Dyo according to everyone, as this is not Kankantum which some say is forbidden to be used in Eiruvin (13a).

Question: In Nidah (20a), the Mishnah states that black is like "Cheres." It is explained that "Cheres" refers to "Charsa d'Ushkafi" (which is clearly black). (Note: It should be noted that while our Gemara in Nidah does not seem to have this text, while Tosfos apparently had this text. We do have the text, in other Gemaros, however, that explain that Kankantum is "Charsa d'Ushkafi.") Vidriolu is green like glass, and this is why it is called Vidriolu. (Note: Why, then, does the Gemara there apparently explain that Kankantum is black?)

Answer: When the Kankantum is being prepared to be put into the Dyo, it becomes black.

Question: This is difficult. The Gemara implies that when one writes with Dyo on top of Dyo, he is not considered as having written regarding the (Torah) laws of Shabbos or Gitin, which is compared to Shabbos later in our Gemara. The Gemara implies that nobody argues that this is incorrect.

Later (20a), we say that if someone wrote a Get Shelo Lishmah, and he then wrote over it again with the writing implement Lishmah, this is the argument between Rebbi Yehudah and the Rabbanan. According to Rebbi Yehudah, this is considered valid writing.

Additionally, Rav Acha concludes in that Gemara that even the Rabbanan agree regarding a Get that such writing is kosher.

Answer: Rabeinu Yitzchak says that when the first writing was not done Lishmah and the second writing was done Lishmah, Rebbi Yehudah and Rav Acha consider it writing, and even the Rabbanan consider it writing regarding a Get. However, in our Gemara when the second writing is not fixing anything, even Rebbi Yehudah agrees that it is not considered writing.

Implied Question: The Gemara in Shabbos (104b) discusses the Mishnah there which says that if someone wrote on top of writing, he is exempt (from being stoned). Rav Chisda says that the Mishnah is unlike Rebbi Yehudah. However, the Gemara did not want to say that the Mishnah is referring to a case where the second writing does not fix anything, which even Rebbi Yehudah agrees is not considered writing. (Note: Why doesn't the Gemara say this? If this were the case, everyone could agree with the Mishnah!)

Answer: This is because the Mishnah implies that generally one is exempt, even if someone wrote a Get or Sefer Torah Shelo Lishmah, and someone went over it with a writing implement Lishmah. This is why the Gemara says that the Mishnah must only be according to the Rabbanan.

However, according to Rav Acha bar Yaakov, the Gemara cannot be talking about any case (of writing over writing). This is because (he holds) the Rabbanan agree regarding a Get that this is considered writing. According to him, the Mishnah (regarding Shabbos) can also be according to Rebbi Yehudah, and is discussing a case where he is not fixing anything with the second writing.

Implied Question: This is considered erasing for the sake of writing (which is the only way one is considered to totally transgress erasing on Shabbos). (Note: Why is this so? He has written over other writing, and will seemingly not write on it again.)

Answer: He will probably go back and write over this again with Dyo.

Implied Question: This is not considered ruining (for which one is exempt from a Torah prohibition). (Note: Why not? It seems like he is merely ruining the first writing!)

Answer: This is because when he writes over this writing (with Dyo as stated above), the top layer of writing will be clearer than if the bottom layer alone was present.

Question: The only reason the Gemara is deducing that there must be writing on the Get is because the man retracted that it was a Get, instead saying that it was a Shtar Pasim. Similarly, regarding a blank paper, if the man would retract saying it was actually a blank paper he would be believed. In contrast, if he would say it was a Get she would be divorced. It would therefore seem that this Tosefta should not be a question on Shmuel (being that the above assumptions can all be understood to be Shmuel's position).

Answer: The Gemara understands at this point that Shmuel meant the woman is considered divorced (not only possibly divorced). Accordingly, there is nothing wrong with a blank paper serving as a Get (as we hold it was a Get whose ink faded away). Therefore, when the husband retracts and says it was actually just a blank paper (that never had a Get written on it), we should say according to Shmuel that he cannot forbid her from remarrying, just as if there was a Get written on it.

Question: How could we think that Shmuel holds she is certainly divorced? It appears to be a blank paper!

Answer#1: Being that he said, "This is your Get" we believe the husband, just like we say that if a husband says, "I divorced my wife," he is believed. He is believed (in the latter case, and similarly in our case) because it is in his hands to divorce his wife.

Answer#2: Alternatively, the case is where two people read it originally, and the husband then received it and divorced her. We do not suspect that he switched the Get with a blank paper. When Shmuel is discussing a blank paper, he does not mean that it was seen to be blank when it was given, as if so, even if it was written with ink that could have faded away it is not a Get. If the Get was already faded when it was given, it is like we say later, "And if it faded what does it matter? Perhaps it just faded now!" (Note: This implies that the Get clearly would not be acceptable if it was given after it faded completely.) Rather, Shmuel's case is that sometime after the Get was given, equivalent to the amount of time that it is possible that the letters would have faded away, people saw that it was blank.

Answer#3: Alternatively, it is possible to answer that at the time that it was given they (the witnesses) saw from afar that it looked like he was giving her a blank piece of paper. However, it is possible that if they had looked closer they would have seen the letters of the Get.

Explanation: The Rach explains that this refers to the water from the peel of a pomegranate. This explanation is also given by the Aruch.

Explanation: Now the Gemara does not have to say that the case is where the checked the Get (with pomegranate water). Even if they did not check it, there is still a suspicion.

However, if they checked it and it did not emit anything, it is certainly not a Get.

Explanation: (Note: The Gemara means that they must read it) before it is given. This is indicated by the fact that the Gemara later answers "it is not necessary, the case is where after they read it etc." (Note: The fact that the Gemara had to establish that it was after they read it indicates that they must read it beforehand.)

If they did not read it, it apparently is not a kosher Get. Being that the Gemara does not answer "the case is where they didn't read it beforehand," implies that if they would not read it beforehand, she would not be considered divorced.

Question: The Mishnah later (80a) gives a case where a person (scribe was commissioned to) write a Get for a man and a receipt for a woman, and he mistakenly gave the Get to the women and the receipt to the man. The man and woman (not realizing the mix up) gave each other the documents. After awhile, the husband realizes that he has the Get (which the woman gave him), and the woman realizes she has the receipt. If she already remarried, she must get divorced from "both" of her husbands.

The Gemara in Yevamos (91b) asks, what was she supposed to have done? The Gemara answers, she should have read the "Get" (and she would have realized that she never received one). However, according to our Gemara, it would seem that the mere fact that the Get was not read beforehand should mean that she is not divorced, even if they had not switched do!

Answer#1: While she would indeed be forbidden to remarry if the Get was not read beforehand, we would not rule that if she already married anyway that she must get divorced.

Answer#2: Alternatively, the case there is where he (the husband upon receiving the Get) placed it out of sight. We therefore give him a fine that he must immediately read it, or it must be read immediately after it is given, as its status had already been ruined (he could replaced it with another document). However, she is not forbidden to marry if it is not read a second time, as we say here that we will not forbid her even though it was not read afterwards.

The Ri used to read a Get before and after it was given. However, it is obvious that if it was not read beforehand and it was read (immediately) after it was given, that she is divorced.