Suppose a woman notices a somewhat complicated veset kavua (in particular, perhaps one that doesn't apply every month). For example, say that she notices that she began to menstruate on 8 Kislev every year for three years1. She continues to observe her veset kavua but she also notices that one year, she begins to menstruate on a simpler cycle (for example, she has her period on the 7th of Shevat, Adar, and Nissan).

Is it possible for a woman to have two chazakot for a veset kavua at the same time, or does the more complicated original veset prevent the simpler veset from kicking in? Is it possible for a simple veset to uproot a complex one?

1. My examples are lav davka. If that case turns out to not qualify as a chazaka, consider another complicated case that does.

  • IIRC, veset kavua is only uprooted if it fails to recur a certain number of times. This implies there isn't a conflict inherent in having multiple vestot kavuot. – Isaac Kotlicky Mar 10 '16 at 20:45
  • @IsaacKotlicky How so? If that is true, it implies that a new chazaka wouldn't uproot the old one, but maybe the new chazaka never gets started. – Daniel Mar 10 '16 at 20:47
  • But what determines a chazaka for a veset is if it "holds," not if it covers ALL occurrences. Therefore, the original complicated chazakah holds for the unusual portion of the cycle, while the simpler one would "get started" to cover the normative progression. – Isaac Kotlicky Mar 10 '16 at 20:48
  • @IsaacKotlicky So? – Daniel Mar 10 '16 at 20:52
  • That site does, in fact, seem to contain contradictory advice for your question - it implies that only a single veset kavua may exist, while simultaneously providing guidelines for having unusual "established" vestot... It seems like the concept of "uprooting one veset kavuah for another" may only apply where the first is dormant and the second then establishes itself, not for when there are overlapping in their kevius. – Isaac Kotlicky Mar 10 '16 at 20:58

In the Shulchan Aruch, Y.D. 189:32 is the case of establishing a vesst concurrent with an existing vesst, i.e. having established a pattern of Rosh Chodesh, and then establishing an additional pattern for day 20 of the month, despite the Rosh Chodesh pattern continuing.

From my related post here.


When a Vesseth is steady, we need its eradication to not waiting it anymore. Is there a contradiction in the fact that we have 2 steady "menses". Is the one who appeared lastly able to eradicate the first? We are going to study this by a case in Rema (Yore Dea 189, 13).

הגה: הָאִשָּׁה שֶׁרָאֲתָה, חוֹשֶׁשֶׁת לְוֶסֶת הַחֹדֶשׁ וּלְהַפְלָגָה, עַד שֶׁתִּקְבַּע וֶסֶת הַחֹדֶשׁ בְּג' פְּעָמִים, אוֹ וֶסֶת הַפְלָגָה בְּד' פְּעָמִים, אוֹ שֶׁתֵּעָקֵר אַחַת מֵהֶן. כֵּיצַד, רָאֲתָה בְּא' בְּנִיסָן וְכ' בּוֹ, חוֹשֶׁשֶׁת לְאֶחָד בְּאִיָּר, מִפְּנֵי רֹאשׁ חֹדֶשׁ נִיסָן. רָאֲתָה בְּאֶחָד בְּאִיָּר אוֹ לֹא רָאֲתָה בּוֹ, חוֹשֶׁשֶׁת לִט' בְּאִיָּר, שֶׁהוּא יוֹם כ' מֵרְאִיַּת יוֹם כ' שֶׁרָאֲתָה. רָאֲתָה בְּט' בְּאִיָּר אוֹ לֹא רָאֲתָה, חוֹשֶׁשֶׁת לְעֶשְׂרִים בְּאִיָּר, שֶׁמָּא קָבְעָה לָהּ וֶסֶת כ' לַחֹדֶשׁ, שֶׁהֲרֵי רָאֲתָה עֶשְׂרִים לְחֹדֶשׁ נִיסָן. וְכֵן הִיא חוֹשֶׁשֶׁת לְעוֹלָם עַד שֶׁתִּקְבַּע וֶסֶת אֶחָד כְּדִינוֹ ‏, ‏

דְּאָז אֵינָהּ חוֹשֶׁשֶׁת לַשֵּׁנִי שֶׁלֹּא נִקְבַּע ‏,... ‏

I am going to explain this according to Chach saif katan 33
The interval of 30 is eliminated by the interval of 20, because the interval of 30 was not steady. But if it had been stable, it would not have been eliminated by the interval of 20. This text is based largely on from Ramban, but it represents only the first opinion quoted by Ramban.

The original text of Ramban is in its book on Hilchoth Nidda, chapter VI, halacha 3 (in Hershler Edition, halacha 2).

כשחוזרת לראות ביום וסתה לכ' אע"פ שחזר הוסת למקומו יש שהורה שצריכה לחוש ליום ל' ממנו ויש שהורה שאינה חוששת כלום משעה שחזר הוסת הקבוע למקומו נעקר שאינו קבוע ולזה דעתי נוטה שאם אין אתה אומר כן תהא אשה זו כל ימיה רואה מכ' ועדיין צריכה לחוש [2]לל ‏' ‏.

I think that your interrogation is accentuated in the case below..

  • A woman was used has to have her menses every 20 days,
  • Afterward the intervals were of 30 days instead of 20.
  • The interval of 30 stabilized and the interval of 20 was eradicate.
  • If the intervals become again of a length of 20 days, Ramban Expose two different opinions:
    1. The first opinion(notice) is the one of Raavad.[1] We cannot eradicate the interval of 30 as long as we have not 3 times an amenorrhea for more than 30 days
    2. and the second opinion (The one that Ramban chose.) is that the interval of 30 is eradicated after 3 intervals of 20 consecutive.
  • But your case is different, and according to both opinions. Two periods coexist, Because intervals and dates are different and not contradictory.


Coexistance of two periodicities based each on dates. can coexist, date + interval can coexist and do not eradicate one another, but two intervals, Machloketh Raavad and Ramban. Rema chooses Raavad.

[1] Raavad, Baaley Hanefesh, Shaar Tikun Vestoth.
[2] What is 30? See Chavath Daath. But it seems 10 days after the day 1: 1---20--30. the count begin at day 1 and not at day 20

  • Isn't this Rama talking about a case where there was no veses k'vua? – msh210 Mar 15 '16 at 0:30
  • @msh210 The rema says "אינו חושש לשני שלא נקבע" =>"אם השני נקבע הוא צריך לחשוש לו". [This is a deduction from his sentence, He choose the opinion of the Raavad]. Do you agree with me? – kouty Mar 15 '16 at 7:12
  • I don't know... – msh210 Mar 15 '16 at 7:18
  • See Pithey Teshuva 12, remember shach 33 (Vesseth Hachodexh is ona benonith). It id mefurash in Ramban halacha 3. Is it right? – kouty Mar 15 '16 at 7:48
  • @msh210 I fixed the link of the ramban in the response, it was wrong. – kouty Mar 15 '16 at 8:00

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