(Continuation of Beraisa - Rebbi): R. Yehudah ben Agra's opinion is Nir'eh (I agree with it) when she did not check. I agree with Chachamim when she checked.

Question: What does "she did (or did not) check" mean?

Answer (Rabanan): (Bein ha"Shemashos is the transition between day and night. We do not know exactly at which moment night begins. R. Yehudah (bar Ilai) holds that Bein ha'Shemashos is when the sky above is dark, but the (western) horizon is not, a period of about 13 minutes. R. Yosi holds that it is the moment before Tzeis ha'Kochavim (when stars become visible). If a sighting was Bein ha'Shemashos, we are concerned lest she saw on both days, i.e. part came during the day, and part at night.) The case is, she did not check her garment (until the third day, and found two Grisim), and she checked herself, but only during Bein ha'Shemashos (at the ends of days one and two) of R. Yehudah, but not during Bein ha'Shemashos of R. Yosi;

The first Tana holds (like R. Yehudah) that Bein ha'Shemashos of R. Yosi is surely night. Since she (checked and) did not see during (the real) Bein ha'Shemashos (i.e. of R. Yehudah) we are concerned only for two sightings;

R. Yosi holds that since she did not check during (the real, i.e. my) Bein ha'Shemashos, perhaps one of the sightings was then (and it counts like two), and she saw three sightings in all.

Question (Rava): Had she checked herself the entire period of (R. Yehudah's) Bein ha'Shemashos, this would be a good answer;

However, perhaps after she withdrew her hand (from checking herself) she saw, while it was still Bein ha'Shemashos!

Answer (Rabanan): Indeed, the case is, her hand (or a compressed cloth that fills the entire place) was in place (checking) all of Bein ha'Shemashos.

(Beraisa - Rebbi): I agree with R. Yehudah ben Agra when she did not check.

Question: What does this mean?

Suggestion: She checked (herself) during Bein ha'Shemashos of R. Yehudah, but not during that of R. Yosi.

Rejection: If so, "she checked herself" means, during both periods. (Rebbi's words imply that they argue in both cases, even when "she checked herself.") It is unreasonable for R. Yehudah (ben Agra) to be concerned then!

Answer: "She did not check" means, she did not check during either period. However, had she checked during Bein ha'Shemashos of R. Yehudah, but not during that of R. Yosi, she would not be concerned (for Zivah).

Inference: Rebbi holds that Bein ha'Shemashos of R. Yosi is night.

Question (Seifa - Rebbi): I agree with Chachamim when she checked.

Question: What does this mean?

Suggestion: She checked during Bein ha'Shemashos of R. Yehudah, but not during that of R. Yosi.

Rejection: This implies that Chachamim are not concerned even when ("she did not check," i.e.) she did not check during either period. This is unreasonable! (Ritva - it is reasonable never to be concerned for Kesamim in one garment, like R. Chanina's opinion. However, since Chachamim are concerned for a Kesem of three Grisim, surely they should be concerned in this case!)

Answer #1: She checked herself during both periods. However, had she checked during Bein ha'Shemashos of R. Yehudah, but not during that of R. Yosi, she would be concerned.

Summation of question: This implies that Rebbi holds that Bein ha'Shemashos of R. Yosi is Safek. (Part is night, and part is day.) He contradicts himself!

Answer: Rebbi means that R. Yehudah ben Agra's opinion is Nir'eh to Chachamim (they agree with it) when she did not check at all. They argue only when she checked during R. Yehudah's Bein ha'Shemashos, but not during R. Yosi's. (This defends Suggestion i,.and it is Answer #2 to Question j:1.)

Contradiction (Beraisa #2 - R. Yehudah ben Agra citing R. Yosi): If a woman found a big Kesem (more than three Grisim), she is concerned (for Zivah). If it is less than this, she is not concerned;

Rebbi: I heard that that R. Yosi is concerned in either case;

He (R. Yosi) explained his reason to me. If a Nidah was not Mafrish b'Taharah (did not check herself at the end of day seven) from Minchah and onwards, she is b'Chezkas Tum'ah. (We are concerned lest she saw at the end of the day and also at night);

I agree with him (R. Yehudah ben Agra) when she checked.

Question: What does this mean?

Suggestion: She checked during R. Yehudah's Bein ha'Shemashos, but not during R. Yosi's.

Rejection: (Rebbi's words imply that they argue even when she did not check.) If so, R. Yehudah is not concerned even if she did not check during either period. This is unreasonable!

Answer: She checked during both periods.

Inference: R. Yehudah ben Agra holds that if she checked during R. Yehudah's period, but not during R. Yosi's, she is not concerned. He must hold that R. Yosi's Bein ha'Shemashos is night!

This contradicts what R. Yehudah ben Agra holds (according to R. Yosi) in Beraisa #1!

If not for Rebbi's comment, we could have answered that in Beraisa #1 she checked only during R. Yehudah's period, and in Beraisa #2 she checked during both periods;

However, Rebbi's words show that in Beraisa #2 she did not check during both periods!

Answer: Tana'im argue about the opinion of R. Yehudah ben Agra;

Tana #2 holds that R. Yehudah ben Agra holds that R. Yosi's Bein ha'Shemashos is after that of R. Yehudah. Tana #1 holds that he holds that R. Yosi's period is during R. Yehudah's.

(Beraisa - Rebbi): If a woman found a Kesem, she is retroactively Teme'ah (from She'as Kivus, the last time she washed the garment) regarding herself (Rashi - Taharos that she touched; Tosfos - calculation of her days of Nidah and Zivah) and Kodshim;

R. Shimon ben Elazar says, she is retroactively Teme'ah (from She'as Kivus) regarding Kodshim, but not regarding herself, for a Kesem cannot be more stringent than a sighting of blood (for which retroactive Tum'ah is at most 24 hours)!

Objection: He himself agrees that a Kesem is more stringent than a sighting regarding Kodshim!

Correction: Rather, R. Shimon ben Elazar says that she is not retroactively Teme'ah regarding Kodshim nor herself, for a Kesem cannot be more stringent than a sighting in any way.

(Beraisa - Rebbi): If a woman found a Kesem, and later saw blood, for 24 hours she attributes the Kesem to the blood. (Tosfos - mid'Rabanan, she is stringent to consider the Kesem like a (Safek) sighting on the previous day. If she will see again the day after the (real) sighting, mid'Rabanan she is a Zavah. Rashi - if she saw blood within 24 hours of the Kesem, she counts the days of Nidah from the day of the Kesem. The Mefarshim ask that a woman is not Teme'ah mid'Oraisa for a Kesem. How can it cause a leniency to immerse earlier?! Tosfos ha'Rosh suggests that this is when the Kesem was seen on the day of her Veses. Rebbi holds that Vestos are mid'Oraisa.)

R. Shimon ben Elazar says, (if she later saw blood,) on the same day she attributes the Kesem to the blood.

Rebbi: R. Shimon's opinion is more Nir'eh than mine, for he fixes (is lenient on) her, and I ruin her.

Question: R. Shimon is more stringent than Rebbi!

Answer #1 (Ravina): We must switch this. (Rebbi prefers his own opinion, for he fixes her, and R. Shimon ruins her. Tosfos - alternatively, he prefers R. Shimon's opinion, for it is better to be stringent.)

Answer #2 (Rav Nachman): We need not switch it. R. Shimon fixes her regarding Zivah. (Rashi - R. Shimon is more lenient. He postpones her days of Zivah until seven days after the sighting. Rebbi is stringent to start them seven days after the Kesem. Tosfos - R. Shimon does not consider her a Safek Zavah if she sees blood also tomorrow, but Rebbi does. Tosfos ha'Rosh - R. Shimon causes her to be stringent lest she is a Zavah, i.e. if she saw a Kesem today and blood tomorrow, he is concerned lest the Kesem came Bein ha'Shemashos (partially yesterday, partially last night), and she is a Zavah. Rebbi says that the Kesem was within 24 hours of the sighting. It was not Bein ha'Shemashos.)

Question (R. Zeira): Is Hefsek Taharah required for Kesamim? (If Leah saw a Kesem, must she check herself Bein ha'Shemashos on the seventh day (from the Kesem) before immersing? Rashba - must she check herself all of Bein ha'Shemashos on the seventh day before counting seven clean days (if it joined to make her a Zavah, or nowadays that women count seven clean days after any sighting)? Tosfos - is the leniency to attribute a Kesem to a sighting only if she checked herself in between the last Kivus and when she found it?)

Rav Asi could not answer. Another time, Rav Asi taught the following:

(Beraisa - Rebbi): One may attribute a Kesem to a sighting within 24 hours.

Version #1 (Rashi) (Rav Asi): Reish Lakish says, this is only if she checked herself (on day seven from the Kesem, which shows that she counts from it);

R. Yochanan says, this is even if she did not check herself. (The Halachah does not depend on when she chooses to count from. However, presumably R. Yochanan agrees that it is normal to be Mafsik b'Taharah.)

Version #2 (Tosfos) (Rav Asi): Reish Lakish says, this is only if she checked herself (less than 24 hours before finding it. Since she cannot be retroactively Teme'ah for 24 hours, we do not decree any retroactive Tum'ah due to the Kesem);

R. Yochanan says, this is even if she did not check herself (within 24 hours, but she did check between Kivus and finding it. Since she cannot be Teme'ah from the time of Kivus, there is no retroactive Tum'ah.)

Version #3 (Rashba) (Rav Asi): Reish Lakish says, this is only if she checked herself (on the day she found the Kesem. If not, we are concerned lest her blood continued to flow. For the same reason, a Hefsek Taharah should be required for Kesamim);

R. Yochanan says, this is even if she did not check herself. (We are not concerned lest her blood continued to flow. Likewise, Kesamim do not require Hefsek Taharah.) (end of Version #3)

R. Zeira: Why didn't you answer my question? Perhaps you knew these teachings, but it did not cross your mind that they answer my question!

Rav Asi: Indeed, you are correct.

(Mishnah): If a woman saw blood Bein ha'Shemashos at the end of any of the following days, she is To'ah (unsure whether her next Dam is Zivah or Nidah):

The 11th day of Zivah. This could be the beginning or end of Nidah. (This will be explained);

The beginning or end of Zivah;

(The last day of Dam Tohar, i.e.) 40/80 days after she gave birth to a boy/girl.

R. Yehoshua: Before fixing (teaching the laws of) the lunatics (this will be explained), let us fix healthy women (who regularly see during certain days of Zivah)!

(Gemara) Question: Why does it say "the beginning or end of Nidah"? It (Bein ha'Shemashos of the 11th day of Zivah) is the beginning of Nidah or the end of Zivah!

Answer (Rav Chisda): It means, if she saw (Bein ha'Shemashos of) the 11th day of Zivah, it is the beginning of Nidah or the end of Zivah. If she saw (Bein ha'Shemashos of) the seventh day of Nidah, it is the beginning of Zivah or the end of Nidah.

(Mishnah - R. Yehoshua): Before fixing the lunatics...

Objection: The women of our Mishnah are not lunatics. They are merely To'os!

Correction: It should say "To'os" instead of lunatics.