Gemara

87b (Mishnah): If blood spurted afar, or is on the knife, it must be covered;

R. Yehudah says, Eimasai' (when is this)? It is if there is other blood. If there is other blood, he is exempt.

88a (Beraisa #1): "V'Chisahu" teaches that blood that spurted or is on the knife must be covered;

R. Yehudah says, says, Eimasai? It is if there is no other blood. If there is other blood, he is exempt.

(Beraisa #2): "And you will cover it" teaches that all the blood must be covered, including blood that spurted and blood left on the place of Shechitah;

R. Shimon ben Gamliel says, this is only if Dam ha'Nefesh (the blood that leaves when an animal dies) was not covered. If it was covered, he need not cover the other blood.

Question: What do they argue about?

Answer: The first Tana holds that "Damo" connotes all the blood. R. Yehudah holds that even some of it is called "Damo". R. Shimon ben Gamliel holds that "Damo" refers to its special blood, Dam ha'Nefesh.

Eruvin 81b (Mishnah - R. Yehudah): What is the case? This refers only to Eruv Techumim...

(Rav Yehudah): The Halachah follows R. Yehudah.

Question (Rav Acha brei d'Rava): This implies that Chachamim argue with R. Yehudah. R. Yehoshua ben Levi taught that whenever R. Yehudah says in a Mishnah 'Eimasai?' or 'What is the case?', he does not argue, rather, he explains the first Tana!

Also Rav Shizbi said in the name of Rav Chisda that Chachamim argue with R. Yehudah!

Answer (Rav Ashi): R. Yehoshua ben Levi, Rav Yehudah and Rav Shizbi are Amora'im. They can argue with each other.

(R. Yochanan): When R. Yehudah says 'Eimasai?', he explains. When he says 'what is the case?', he argues.

Sanhedrin 24b (Rami bar Chama): Betting is Asmachta (the winner may not take the money. It is theft.)

Question (Mishnah - R. Yehudah): Eimasai (that they are Pasul for testimony)? It is when they have no other profession. If they have another profession, they are Kesherim.

If it is theft, he is disqualified even if he has another profession!

Suggestion: Chachamim argue with R. Yehudah, and they disqualify because it is Asmachta.

Rejection: R. Yehoshua ben Levi and R. Yochanan taught that whenever R. Yehudah says 'Eimasai?', he explains the first Tana;

Answer: Rami bar Chama is an Amora. He argues with R. Yehoshua ben Levi and R. Yochanan. He holds that 'Eimasai?' shows that R. Yehudah argues.

Question: Surely, all agree that R. Yehudah argues with Chachamim!

(Beraisa): Whether or not he has a profession, he is disqualified.

Answer: The Beraisa is like R. Yehudah in the name of R. Tarfon;

(Beraisa - R. Yehudah citing R. Tarfon): Acceptance of Nezirus requires Hafla'ah (certainty. Likewise, betting is Asmachta.)

Gitin 7b (Beraisa #1): Bringing a Get in a boat is like bringing a Get in Eretz Yisrael.

Contradiction (Beraisa #2): It is like bringing a Get in Chutz la'Aretz.

Answer #1 (R. Yirmeyah): Beraisa #1 is like Chachamim, and Beraisa #2 is like R. Yehudah.

(Mishnah): If soil of Chutz La'aretz is in a boat in Eretz Yisrael, Ma'aser and Shemitah apply to what grows in it;

R. Yehudah says, Eimasai? It is only if the boat scrapes the bottom of the river.

(R. Zeira): R. Yehudah and Chachamim argue also about an elevated flowerpot (e.g. on a tripod).

Answer #2 (Rav Nachman bar Yitzchak): The Beraisos argue about the Mediterranean Sea.

Rishonim

Rif (29b): The Halachah follows the first Tana of our Mishnah, like R. Yehudah explained. The Halachah does not follow R. Shimon ben Gamliel. Whenever R. Yehudah says 'Eimasai?' or 'what is the case?', he comes to explain Chachamim. Even R. Yochanan disagrees only about 'what is the case.' He agrees about 'Eimasai?'

Rebuttal (Ba'al ha'Ma'or 29a): The Gemara says that it is a three-way argument. This shows that R. Yehudah argues (with the first Tana). He does not explain. Normally, whenever R. Yehudah says 'Eimasai?', he comes to explain. In a case like this, we do not learn from the general rule. It was not clear from the Mishnah that R. Yehudah argues; the Beraisa and Gemara make this clear. The Halachah follows Chachamim, who obligate covering all the blood, even what spurted and is on the knife.

Defense (Milchamos Hash-m): The Gemara asked 'what do they argue about?' regarding R. Yehudah and R. Shimon ben Gamliel. The first Tana of both Beraisos holds that "Damo" connotes all the blood. R. Yehudah explains that some of all the blood must be covered. I.e. if one covered some of the blood, whether or not it was Dam ha'Nefesh, he is exempt. If he did not cover, even if he found only blood that spurted, of either kind, or blood on the knife, he must cover it. R. Shimon ben Gamliel argues. He obligates covering only the special blood, i.e. Dam ha'Nefesh. Both in the Mishnah and Beraisa, he (R. Yehudah) explains the first Tana. The first Tana of the other Beraisa taught Stam 'this teaches that all the blood must be covered.' The verse included blood that spurted and blood left on the place of Shechitah. He does not distinguish. That Tana holds that 'blood' connotes all the blood. Regarding this, the Gemara asked 'what do they argue about?' The Rif connotes like this Perush. The Ba'al ha'Ma'or said (in a case like this) we do not learn from the general rule. This is wrong. In many places, the Gemara asks from this rule. It never answered 'the rule does not apply here.' In Gitin, it seems like there is an exception. R. Yirmeyah answered that one Beraisa is like R. Yehudah, and the other is like Rabanan', and he cited a Mishnah in which R. Yehudah says 'Eimasai?' R. Zeira says that R. Yehudah and Chachamim similarly argue in another case. I explain that the entire Mishnah is R. Yehudah. He explains the first Tana. The Beraisa, or R. Yirmeyah and R. Zeira, disagree with the general rule. They are Amora'im. We say in Sanhedrin and Eruvin that some disagree with this rule. In Gitin, Rav Nachman (bar Yitzchak) explained the argument differently. He holds that 'Eimasai?' comes to explain. We hold like this. We do not uproot the general rule, if the Gemara did not say so. The Rishonim rule like this, e.g. the She'altos, R. Chananel and all the latter Rabanan in Spain. People conduct like this.

Ran (DH b'Mai): The Rif holds that we say 'the first Tana holds that "Damo" connotes all the blood', i.e. the first Tana of the Beraisa. We say that R. Yehudah holds that it connotes even some of the blood, i.e. he explains the first Tana of the Mishnah. Our Mishnah did not name the first Tana, and R. Yehudah explains him, so we call this R. Yehudah's opinion. They hold that some of the blood suffices. This is why they exempt blood that spurted, even if it is Dam ha'Nefesh, as long as there is other blood. R. (Shimon ben) Gamliel obligates covering all the Dam ha'Nefesh. This is why the Rif rules like the first Tana of the Mishnah, like R. Yehudah explains.

Ran (ibid.): In some texts of the Gemara, in Beraisa #2 the first Tana says that all the blood must be covered, and R. Yehudah says that this is only when there is no other blood. This is why the Ba'al ha'Ma'or says that since in the Beraisa, R. Yehudah says Eimasai to argue, presumably also in the Mishnah he argues. The first Tana of the Mishnah and the Beraisa are the same. We hold that Eimasai explains, i.e. when there is no proof that they argue. Sanhedrin 25a connotes like this. Rami bar Chama holds that even Eimasai is to argue, when we can prove this. According to this, if blood spurted afar, or is on the knife, it must be covered, even if there is other blood, like the first Tana. Perhaps there is no proof even according to this text. Perhaps Eimasai argues only in a Beraisa, but not in a Mishnah. Therefore, l'Halachah, we do not like the first Tana of the Beraisa and abandon the first Tana of the Mishnah. Also the Rambam says so.

Rambam (Hilchos Shechitah 14:8): If blood spurted afar, or is on the knife, if there is other blood, it must be covered.

Ra'avad: This is like the Rif, who holds that R. Yehudah explains (the first Tana), because whenever R. Yehudah says 'Eimasai', he explains. Others disagree, because the Gemara explains that they argue about how to expound.

Rosh (6:10): Even though we say in Sanhedrin that whenever R. Yehudah says 'Eimasai', he explains, this is only in a Mishnah, but not in a Beraisa. The text in Eruvin says 'whenever R. Yehudah says 'Eimasai', he explains in our Mishnah'... R. Tam says that the Halachah does not follow Rabanan, rather, R. Yehudah. Even though R. Yehudah argues with them in a Beraisa, in the Mishnah he explains them. This is primary. Also the Rif rules like Rabanan of our Mishnah, like R. Yehudah explains. This requires investigation. Rami bar Chama and Rav Chisda hold in Sanhedrin that when it is clear, even in a Mishnah 'Eimasai' is to argue. Here he clearly argues in the Mishnah, just like he argues in the Beraisa! In some texts, in Beraisa #1 Chachamim do not say that all the blood must be covered.) R. Yehudah says, Eimasai... According to this, also in the Beraisa R. Yehudah comes to explain. These Rabanan are the first Tana of R. Shimon ben Gamliel. If so, the Halachah follows Chachamim of the Mishnah, like R. Yehudah explains.

Tosfos (Gitin 7b DH Amar): Our Gemara connotes that R. Yehudah says Eimasai to argue. In Eruvin and Sanhedrin, R. Yehoshua ben Levi and R. Yochanan agree that Eimasai explains! We can say that R. Yirmeyah here holds like Rami bar Chama, who holds that even 'Eimasai' is to argue. Alternatively, the rule is only for Mishnayos. Here it is a Beraisa. The Mishnah in Chalah does not discuss the boat scraping the ground. Tana'im argue about whether R. Yehudah always comes to argue in a Mishnah (when he says Eimasai). However, in Eruvin and Sanhedrin we prove from Beraisos that R. Yehudah argues also in the Mishnah. Perhaps the Mishnah is like the other Tana! Since the Gemara knew an explicit Beraisa in which R. Yehudah cites R. Tarfon, we say that also the Beraisa is this opinion. We must say that only in the Mishnah R. Yehudah comes to explain, for in Chulin it explicitly says that he argues about how much blood must be covered. R. Tam rules like R. Yehudah in the Mishnah. However, perhaps the primary opinion is Chachamim of the Beraisa, and R. Yehudah of the Mishnah is an individual against a Rabim in the Beraisa. The Gemara in Sukah (14) says like this.

Hagahah: Perhaps Tosfos refers to Sukah 19b.

Poskim

Shulchan Aruch (YD 28:15): If blood spurted afar, or is on the knife, if there is other blood, it must be covered.

Beis Yosef (DH v'Chasvu): According to the text in which the first Tana of Beraisa #1 obligates covering all the blood, R. Yehudah comes to argue. Even according to this, the Halachah follows R. Yehudah. Tosfos, the Ran, Rif, Rambam, Semag, Semak, Rashba and Tur rule like this.

Gra (10): Even though Rav Chisda and Rami bar Chama disagree, we hold like R. Yehoshua ben Levi and R. Yochanan. Even though we say that it is a three-way argument (and R. Yehudah and the first Tana disagree), this refers to the first Tana of the Beraisa. R. Yehudah explains only in the Mishnah. We hold like our Mishnah. Also, 'the first Tana' can refers to the first Tana of R. Shimon ben Gamliel, especially according to our text, in which the first Tana of Beraisa #1 expounds that all the blood must be covered. R. Yehudah comes to explain even in the Beraisa. However, the Sugya in Gitin holds that Eimasai comes to argue.