(Mishnah): If Melikah was done with a knife, the bird is Neveilah, and it has Tum'as Beis ha'Beli'ah (it is Metamei one who swallows a k'Zayis of it, and his garments)!

Chulin 19b (Benei R. Chiya): One moves the Simanim (the windpipe and foodpipe) behind the spine and does Melikah.

20a - Question (R. Yanai - Mishnah): Anything Kosher for Shechitah is invalid for Melikah. Anything Kosher for Melikah is invalid for Shechitah.

Suggestion: This teaches about moving the Simanim behind the spine. (It is Kosher for Shechitah, and hence invalid for Melikah.)

Answer (R. Yirmeyah): No, it excludes Molich u'Mevi (moving the knife or fingernail away and returning it), which is Kosher for Shechitah and invalid for Melikah.

Question: This is like the opinion that Molich u'Mevi is invalid for Melikah. According to the opinion that it is Kosher for Melikah, what does the Mishnah teach?

Answer: Benei R. Chiya must hold that Molich u'Mevi is invalid for Melikah.

(Rav Kahana): The Mitzvah of Melikah is to (press the fingernail and) cut straight down into the neck. This is the Mitzvah.

Suggestion (R. Avin): He holds that only this is Kosher, but not Molich u'Mevi.

Rejection (R. Yirmeyah): If this is Kosher, all the more so, Molich u'Mevi is Kosher!

Question: If so, what does he exclude (with the words 'this is the Mitzvah')?

Answer: He means that even this (cutting through pressing) is the Mitzvah.

20b (Ze'iri): If the neckbone and most of the flesh were cut, the animal is a Neveilah.

Question (Rav Chisda): A Mishnah already teaches this!

(Mishnah): If Melikah was done with a knife, if one eats the bird, he and the clothes he is wearing (when he swallows) become Tamei (since the bird is a Neveilah).

If cutting the neckbone and most of the flesh would make it only a Tereifah, but not a Neveilah, Melikah with a knife would be like slaughtering a Treifah (since the Simanim are cut after the neckbone and most of the flesh). This cannot be, for a slaughtered Treifah is not Neveilah!

Answer: Melikah done with a knife makes a Neveilah, for it is not at all like Shechitah!

Question: Why is it unlike Shechitah?

Answer #1 (Rav Huna): It is Chaladah (the knife is covered, or the Simanim are cut in the wrong direction).

Answer #2 (Rava): It is Drasah. (He cuts through pressing, and not through Molich u'Mevi).

Rav Huna did not answer like Rava, for he holds that Molich u'Mevi is valid for Melikah.

Rambam (Hilchos Shechitah 3:10): If one inserted the knife under the skin and slaughtered the Simanim normally, or Hichlid (concealed) the knife under tangled wool, or he spread a cloth over the knife and the neck and slaughtered under it, since the knife is not exposed, it is Safek Neveilah.

Hagahos Maimoniyos (6): Re'em says that one may not make a small hole in the skin and insert the knife and slaughter, even though the knife is exposed opposite the Simanim. Sefer ha'Terumah rules that b'Di'eved it is Kosher, since the knife is exposed opposite the Simanim. If one slaughters with the end of the knife which is covered at the time of Shechitah, surely it is Pasul. Rashi (20b DH Malak) says that Melikah with a knife has Tum'as Beis ha'Bli'ah. Rav Huna says that this is due to Chaladah. One must be careful not to be too concerned for the skin.

Rambam (Hilchos Ma'aseh ha'Korbanos 6:23): To do Melikah, he may go Molich u'Mevi, or press it down. He cuts the spine and neckbone without most of the flesh.

Ri Korkus: R. Avin thought that Molich u'Mevi is Pasul for Melikah. R. Yirmeyah taught that all the more so, Molich u'Mevi is Kosher. Also, Rava and Rav Huna argued about this, and Rav Huna is Machshir. Therefore, we are Machshir.

Kesef Mishneh: The Rambam rules like Rav Huna, for R. Avin and R. Yirmeyah hold like him.

Rashi (Chulin 20a DH Kotzetz): Rav Kahana teaches that he cuts without Molich u'Mevi. He does not exclude Molich u'Mevi, for all the more so it is Kosher! The Torah explicitly excluded a knife and the neck. Whatever it did not explicitly exclude, it is better to do Melikah like Shechitah.

Hagahos Ashri (Chulin 1:25): Rashi in Zevachim says that Melikah with the end of a knife is Chaladah, for he inserts the end under the bone. Therefore, one who is concerned for the skin and cuts with the end of the knife, he must be careful lest it be covered with skin and he cut Simanim with the end, for this is Chaladah.

Rashi (Kesav Yad, 68a DH Malak): Melikah with a knife is not Shechitah, because it is with the end of the knife. He cuts the spine and neckbone until he reaches the Siman. He must make a small cut, lest he cut most of the flesh before reaching the Siman. This is possible only with the end of the knife, and this is Chaladah, like it says in Chulin.

Tosfos (20b DH Mipnei): Our Gemara refutes Rashi. It is called Chaladah even though the Hava Amina is that he cuts most of the flesh!

Rashi (68a DH Malak): Melikah with a knife is not Shechitah, like it says in Chulin, because it is Chaladah, because it is Drasah.

Note - Drasah does not cause that it is Chaladah! Surely the text should say 'or because it is Drasah' (like Mesores ha'Shas) or 'and because it is Drasah' (Shitah Mekubetzes 17).

Yam Shel Shlomo (Chulin 1:42): We should say that the Halachah follows Rava against Rav Huna, for he is Basra (lived later)! Perhaps the Rambam rules like Rav Huna because we concluded 'Bnei R. Chiya hold that Molich u'Mevi is Pasul', which connotes that this is not the Halachah. R. Avin thought to say like Rava, but R. Yirmeyah corrected him, for whatever the Torah did not explicitly say cannot be like Shechitah, it is better to do Melikah like Shechitah. Also, the text should not say 'Rava'. We do not find that he argued with Rav Huna. Rather, it should say 'Rabah'. Rashi (20a DH ha'Nicha) says that Rabah argues with Rav Huna. Since Molich u'Mevi is Pasul, the Halachah follows Rav Huna, and such a Shechitah is Chaladah. Rashi (Zevachim 68a) says that Melikah with a knife is Chaladah, for he inserts the end of the knife, for he does not want to cut the majority of the flesh with the ncb before the Simanim. Even though Tosfos said that here we cannot explain like this, for here in the Hava Amina he cuts most of the flesh, this does not refute Rashi. We can say that in the conclusion, Rav Huna considers this Chaladah! Piskei ha'Tosfos (62) says that this is Chaladah. Semag says so only if he cuts with the end of the knife. One could say that Re'em is stringent only l'Chatchilah, but Hagahos Maimoniyos says that Re'em considers it Neveilah. However, Tosfos and Semag say 'one need not be concerned', which shows that it is l'Chatchilah. Perhaps even Re'em holds that it is Neveilah only if he intends (to make only a small hole in the skin). One must be stringent when he is concerned for the skin.

Note - Tosfos (Menachos 36a DH Amar) proved that Rava never saw Rav Huna, for Rav Huna died before Rav Yehudah, and Rava was born when Rav Yehudah died. The Chasam Sofer (Sukah 42a (16)) questioned this proof, for there were two Rav Huna's, like Tosfos (Chulin 13a) proved.

Shulchan Aruch (YD 24:9): If one in concerned for the skin, he must be careful not to make a big hole and slaughter with the end of the knife and it is covered by the skin. However, if he slaughters with the middle of the knife, he need not be concerned if the end of the knife is covered by the skin, since the part of the knife that cuts is not covered. Some are stringent even about this. One should be concerned for his opinion l'Chatchilah.

Beis Yosef (DH Kasuv): Sefer ha'Mitzvos says that one must be careful not to slaughter with the end of the knife. The Re'em is stringent even if he slaughters with the middle of the knife. Hagahos Maimoniyos says that Semag is Machshir with the middle of the knife only b'Di'eved. Even though Semag connotes that he permits l'Chatchilah, since Re'em forbids, it is proper to concerned l'Chatchilah.

Bach (5): Tosfos brought from Rashi that when the end of the knife is concealed, it is Chaladah. Also Hagahos Ashri (25) says so. We hold like this, unlike the Shulchan Aruch, who is Machshir b'Di'eved.

Taz (5): This is not difficult for the Shulchan Aruch. Rashi discusses when he cuts the Simanim with the point of the knife. Since he must avoid cutting most of the flesh with the neckbone, he must insert the knife under the flesh on the neckbone, lest he cut it, and under the flesh he cuts the neckbone and Simanim. The knife is covered in the place of Shechitah. Hagahos Ashri and the Roke'ach explicitly say so.

Bach (Kuntres Acharon): One must be careful when slaughtering with the end of the knife, for then it is prone to be covered with skin. One must be careful that the knife is exposed at the end where he cuts. However, when he slaughters with the middle, surely he need not be concerned if the end is covered. Also the Prishah (3) says so.

Shach (9): In the first case, when he slaughters with the point and there the knife is covered by the skin, the Mechaber disqualifies even b'Di'eved. The Beis Yosef connotes like this. The Levush says that one must be careful not to cover any part of the knife at the time of Shechitah, whether opposite the Simanim or opposite the knife not opposite the Simanim. He did not explain well; the first case is Pasul even b'Di'eved.

Gra (9): Regarding mid'Oraisa laws, we follow the stringent opinion (that this is Chaladah - Chulin 20b). Even though Tosfos rejected Rashi, the Poskim defend Rashi.

Tosefes Merubah (in Otzar Meforshim in Shulchan Aruch ha'Shalem): One must be careful to remove the rope from the animal's neck at the time of Shechitah. One should disqualify the Shechitah if it covered even a hair's breadth of the knife. Similarly, if one must wrap a cloth on the knife, e.g. it has a nick and it is Yom Tov or pressed circumstances so one cannot sharpen it (to remove the nick), one must be careful that the cloth not extend further along the length of the thick side of the knife than along the blade. Perhaps he will cut with a part of the blade and opposite it (on the thick side) it was covered with the cloth (Simlah Chadashah 13)! Tevu'os Shor (15) says that this is not Chaladah, since the Shechitah is seen from the ends of the knife.