Gemara

(Mishnah): We slaughter right where Semichah was done. Shechitah is done Tekef to (right after) Semichah.

This means that Shechitah is done at the same place in the Azarah as Semichah because Shechitah is right after Semichah.

Zevachim 33a (Beraisa): Shechitah must always be Tekef to Semichah, except for Asham Metzora, for which Semichah is by Sha'ar Nikanor. The Metzora cannot enter the Azarah until the blood of the Asham is put on him and the blood of the Chatas is Nizrak.

Inference: Bi'ah b'Miktzas is Bi'ah. If it were not, he could stick his hands in and do Semichah!

Rejection (Rav Yosef): The Tana is R. Yosi b'Rebbi Yehudah, who says that Tzafon (the north part of the Azarah, where we slaughter Asham) is far from the end of Sha'ar Nikanor. (Even if he sticks his hands in, Shechitah cannot be Tekef to Semichah.)

Berachos 42a (R. Chiya bar Ashi): Shechitah must be Tekef to Semichah, Tefilah (Shemoneh Esre) must be Tekef to Ge'ulah (Ga'al Yisrael), and Berachah must be Tekef to washing.

51b (Mishnah -Beis Hillel): First we mix the cup, then we wash the hands.

52b: They permit using a cup whose outside is Tamei, so we are concerned lest the cup be Metamei wet hands. Also, one must eat Tekef to washing.

Pesachim 106a (Rav Berona citing Rav): One who washed his hands should not say Kidush (it is a Hefsek (interruption) between washing and ha'Motzi. Rather, he hears Kidush from someone else.)

Rav Yitzchak bar Shmuel: You erred! When Rav preferred bread, he was Mekadesh on bread. When he preferred wine, he was Mekadesh on wine.

115a (Rav Chisda): (Even though) one washed his hands for the first dipping (at the Seder), he washes for the second dipping.

Question: Why must he wash again? He already washed (knowing that he will dip again)!

Answer: Since we say Hagadah and Hallel in between, perhaps he was distracted and touched (something that is Metamei the hands).

Rishonim

Rif (Berachos 30a): Even after the table was removed, one may eat. We do not hold like the teachings here. (On 42a, some forbid eating after the meal, or after the bread was taken away...). Rather, as long as he did not wash, he may eat. Berachah must be Tekef to washing.

R. Yonah (DH Sheloshah): R. Zeira omitted that one may eat Tekef to washing, for he lists only matters learned from verses.

Rambam (Hilchos Berachos 6:20): One says Birkas ha'Mazon Tekef to Netilas Yadayim.

Rosh (Berachos 6:31): Berachah must be Tekef to Netilah. Some distinguish between eating and drinking (and allow drinking after Mayim Acharonim, i.e. washing before Birkas ha'Mazon). This is unreasonable.

Tosfos (Berachos 52b DH Tekef): We did not need to list (among things that must be Tekef) that one must eat immediately after washing, since it is in the Mishnah. (It is known.)

Rashi (33a DH Merchak): The Tana holds that Tzafon is only to the north of the Mizbe'ach, which is 22 Amos west of Sha'ar Nikanor (Midos 5:1). Therefore, it is impossible to do Semichah from the Ezras Nashim, and Tekef l'Semichah Shechitah in the north.

Tosfos (Sotah 39a DH Kol): Our Gemara says that "lift your hands in Kedushah and bless Hash-m" discusses Birkas Kohanim. The Yerushalmi holds that it discusses washing for Birkas ha'Mazon. Berachos 42a connotes similarly. We can learn the Shi'ur of Tekef from Shechitah of Asham Metzora, which cannot be Tekef to Semichah, for it is too far (22 Amos) from Sha'ar Nikanor.

Question (Magen Avraham OC 166:3): In Zevachim, the Hava Amina was that one may slaughter anywhere in the Azarah. If so, even if partial Bi'ah were Bi'ah, one could do Semichah outside the opening of the Azarah, and slaughter nearby! Rather, going from place to place, even a small distance, is a Hefsek. In Menachos, it says that we slaughter where we do Semichah. This requires investigation.

Answer (Gra 166:3): L'Chatchilah, one should not delay even for one step. Tosfos discusses what is Me'akev.

Poskim

Shulchan Aruch (OC 165:2): If many are at a meal, the Gadol washes first. The Rosh used to wash last, in order that he not interrupt or speak.

Magen Avraham (4): All agree that 'Berachah is Tekef to Netilah' refers (at least) to Mayim Acharonim, yet one may talk between Mayim Acharonim and Birkas ha'Mazon! Perhaps the Shulchan Aruch forbids another matter, which is a Hefsek, but two or three words is not a problem. All the more so, if asked something, one may answer yes or no.

Mishnah Berurah (7 and Sha'ar ha'Tziyon 13): Even a small conversation is forbidden, like the Magen Avraham says (179:1), unlike he said here.

Shulchan Aruch (166:1): Some say that one need not be careful about a Hefsek (interruption) between Netilas Yadayim and ha'Motzi. Some say that one must be careful. It is good to be careful.

Beis Yosef (DH u'Mah she'Chasav Rabeinu): The Tur says that the Rif holds that one need not be concerned for a Hefsek. This is difficult. The Rif merely cited the Gemara. However one can understand the Gemara, he can understand the Rif!

Bach (2): The Rif must hold that 'Berachah is Tekef to Netilah' refers to Mayim Acharonim. If not, he would have no source to reject the teachings about eating after the meal!

Beis Yosef (DH u'Mah she'Chasav d'Mitoch): The Yerushalmi says that one who blesses right after Netilas Yadayim will not be harmed the entire meal. This implies that it discusses Mayim Rishonim (washing before the meal). It cannot refer to Mayim Acharonim, for he already finished the meal. What was, was! (He cannot change whether or not he was harmed during the meal.) It is good to be careful also about Mayim Rishonim.

Gra (2): The first opinion explains that if one blesses right after Mayim Acharonim, the Satan does not prosecute about the meal.

Beis Yosef (DH Garsinan): In Pesachim we require washing again for the second dipping. Since we say Hagadah and Hallel in between, perhaps he was distracted and touched. Regarding one who washed his hands before Kidush (he does not say Kidush. Rather, he hears it from someone else), Kidush is not considered a Hefsek! There, it is because he intends to eat.

Taz (1): R. Yo'el and the Rif (brought in the Tur) say that one need not be concerned for a Hefsek. They hold that 'Berachah must be Tekef to washing' refers only to Mayim Acharonim. This is difficult, for we explain that Beis Hillel hold that we mix the cup and then wash the hands, for one must eat immediately after washing. This refers to Mayim Rishonim! Tosfos says that we did not need to list that one must eat immediately after washing, since it is in the Mishnah. The Bach says that R. Yo'el holds that it was not listed because the Halachah does not follow it. (We hold like the first reason for Beis Hillel.) I say that we listed the three cases in which one may not delay idly. One may wash and delay idly before eating. It is forbidden only to do something in between. Tosfos (Pesachim 106b DH Zimnim) says that mixing a cup (of wine) with hot water is a Hefsek, since one must be precise not to put in too much or too little. R. Tam says that Beis Hillel discuss during the week. If one washes before mixing, perhaps he will engage in other things and not eat. On Shabbos there is no concern, for the table is set in front of him. R. Yo'el permits only a Hefsek sitting idly. Surely one may not do an action, lest this lead to Hesech ha'Da'as (diverting his mind from guarding his hands).

Magen Avraham (2): The Shlah says that every day, one should pray for his food before Netilas Yadayim. If he forgot, he may pray after Netilah. The custom is to say "Hash-m Ro'i Lo Echsar..." between Netilah and ha'Motzi.

Mishnah Berurah (3): It is better to say Hash-m Ro'i after eating a little.

Kaf ha'Chayim (4): One should say Hash-m Ro'i before Netilah. If he forgot, he should say it after eating a k'Zayis. However, if one did not say "Einei Kol Elecha Yesaberu..." and "Pose'ach Es Yadecha..." before Netilah, he says them between Netilah and ha'Motzi, for this is the primary prayer for income. If one did not say "Se'u Yedeichem Kodesh..." before Netilah, he does not say it at all, for the Ari Zal did not mention it.

Yabi'a Omer (8 OC 20:6): The Shulchan Aruch says that it is good to avoid a Hefsek between Netilah and ha'Motzi. This implies that letter of the law, it is permitted. For this reason, Mor u'Ktzi'ah permits blessing Asher Yatzar in between or saying a short Tefilah.

Magen Avraham (2): The Maharshal says that the Ba'al ha'Bayis should tell the Gadol to wash last. If he told him to wash first, he must do so. He may not say 'they will wait. I will not wait.' He washes, and waits silently. If they asked him Divrei Torah, he may answer. The Bach forbids even Divrei Torah. Even sitting (silently) is a Hefsek. Therefore, the Gadol may refrain from washing first, since (he will say ha'Motzi, and) it is worse if the one who says ha'Motzi interrupts. Also, if others (wash first and) see that there is a delay, they can take bread and bless quietly for themselves.

Mishnah Berurah (1): The first opinion is concerned only for an action in between, or much talk. A little talking is not a problem, since the table is set and he is ready to eat immediately.

Mishnah Berurah (2): The second opinion forbids a mere delay or any words, unless they are for the needs of the meal.

Kaf ha'Chayim (3): One must prepare beforehand what he needs for Netilas Yadayim and ha'Motzi, e.g. a towel, table, bread, etc., lest he need to interrupt after Netilah, and to enable saying ha'Motzi immediately.

Mishnah Berurah (158:44): L'Chatchilah, one must bless Al Netilas Yadayim before drying. Some say "Se'u Yedeichem Kodesh..." after washing, and do not finish (and begin Al Netilas Yadayim) until their hands are dry. This is wrong.

Kaf ha'Chayim (3): The Maharsha (Shabbos 9b Rashi DH Ha) says that even Bnei Bavel would not loosen the belt between Netilas Yadayim and eating, due to Hefsek. Aruch ha'Shulchan (1) says that it is not a Hefsek, for it is a need of the meal. L'Chatchilah, one should loosen it before Netilah or after eating a k'Zayis. B'Di'eved, if he loosened it in between, it is not a Hefsek. Kitzur Shulchan Aruch (41:2) permits answering Amen in between. This is obvious.

Yabi'a Omer (ibid. 5): Drying is part of the Mitzvah, so one may not answer between Al Netilas Yadayim and drying. One may answer after washing, before Al Netilas Yadayim.

Drushei ha'Tzlach (4:22, cited in Yabi'a Omer): Many Chachamim are careful to avoid a Hefsek between Al Netilas Yadayim and ha'Motzi, but not between washing and Al Netilas Yadayim. They err. Between washing and Al Netilas Yadayim a Hefsek is forbidden. Between Al Netilas Yadayim and ha'Motzi, it is merely good to avoid a Hefsek.

Yabi'a Omer: Presumably, he means that between drying and ha'Motzi is merely good to avoid a Hefsek. Before drying the Mitzvah was not finished, so letter of the law one may not interrupt. Eliyahu Rabah (162:1) brings from the Ari Zal to say "Se'u Yedeichem Kodesh..." after washing and before the Berachah. The Mishnah Berurah permits (as long as he finishes before drying). Nimukei Orach Chayim (158:4) forbids.

Kaf ha'Chayim (7): Even a small amount of talk, even Divrei Torah, is a Hefsek.

Rema: If one delayed the time to walk 22 Amos, this is called a Hefsek.

Mishnah Berurah (4): We measure the time from when he dried his hands.

Kaf ha'Chayim (9): We are not concerned if he took a long time to dry his hands, for one must dry them well. The same applies to Mayim Acharonim.

Magen Avraham (3): One should not delay without need.

Mishnah Berurah (5): If he went to another house, some are stringent even for a small distance.

Kaf ha'Chayim (10): This is even if he can see the place where he washed. Within one house, even from room to room is not a problem, if it is within the time to walk 22 Amos. Going from where he washed to the place of the Seudah is not a problem, since it is a need of the meal. L'Chatchilah, one should wash close to where he will eat, if possible. It is proper to dry near where he will eat.

Mishnah Berurah (6): B'Di'eved, if he delayed or interrupt, he need not wash again, unless he had Hesech ha'Da'as from guarding his hands.

Taz (2): The Maharshal (Teshuvah 34) says that this is only for Mayim Acharonim. For Mayim Rishonim, it is merely good to be careful (to avoid a delay).