From the Rav’s Desk: Saw flow by Bein Hashmashos-How to calculate Veses and five days?

Saw flow by Bein Hashmashos-How to calculate Veses and five days?

  1. Question: [Wednesday, 9th Iyar 5781]

I began my flow [or at least I noticed it] during the time of Bein Hashmashos, between sunset and nightfall. When is considered the day of the start of my period to be marked on the calendar and from when do the five days begin?


This matter is debated amongst the Poskim and Rabbanim of today. In accordance to what I received in Shimush, regarding the marking on the calendar for the sake of making a Kevius Veses and the Chashash Vestos calculation, it is proper to be stringent to mark both the day and night and calculate from both of them [i.e. separate two Onos for the Veses Hachodesh/Haflaga/Beinonis etc] even though the main calculation is really from the night. However, regarding the counting of the five days, if the blood was seen within 9 minutes from sunset, one can be lenient to count the previous day [i.e. the daytime, as if one saw before sunset] as the first day. Practically, however, if it is not too difficult for the couple, one should count the five days from nighttime being in this matter is debated amongst the Poskim. [Also, to note that in the various online calendars that I have seen, they do not allow for separate calculations of the five days and that of the Vestos, and hence they will calculate everything based on the nighttime if one saw after sunset, even though in truth there is a discrepancy as we explained above.]

Explanation: It is unclear from the ruling of the Shulchan Aruch, as well as from the commentary of Admur, as to whether we follow sunset or nightfall with regards to the Vestos calculation and waiting of five days or if we view the time between sunset and nightfall as a doubt. Practically, regarding the Vestos calculation, from the letter of the law if one saw between sunset and nightfall, one only has to mark the nighttime on the calendar, either due to the fact that we follow sunset or due to the fact that whenever there is a doubt regarding when one saw the flow one only marks the time that for certain the flow was seen, which is at night. However, it is proper to be stringent in all cases of doubt to mark both the daytime and nighttime, and hence since it is debated amongst the Poskim as to whether Bein Hashmashos is defined as night or as a doubt, and the simple implication of Admur is that it is considered a doubt, therefore both should be marked due to the stringency. [This means that all of the Vestos calculations of Hachodesh, Haflaga and Beinonis are calculated from two different dates, and she will therefore end up separating double that month.] However, in the event that one chooses to follow the letter of the law and only mark one timeframe, than one must mark the nighttime being that this is the main time from the letter of the law. Now, all the above is regarding the Vestos calculation, however regarding the wait of the five days many Poskim write that based on the reason behind the added fifth day of delay [that it is due that perhaps she will have intimacy during Bein Hashmashos], that we treat Bein Hashamashos as daytime and therefore one may begin counting the five days from the daytime [i.e. the previous day] even though regarding the Vestos calculation she mainly calculates from the nighttime. Now, while other authorities argue on this and write that also regarding the five day wait one is to consider it as nighttime, practically, I received in Shimush that one may be lenient, although if it is not too difficult, it is proper to be stringent like those opinions who rule that one counts the five days from night.


Sources: See regarding the Vestos calculation: Michaber Y.D. 184:4 [count from later time whenever in doubt when saw blood] Admur 284/11-12 [that regarding Vestos calculation we follow sunrise and sunset] Admur 184:19 based on Shach 184:13 and Bach 184 [that if saw by Bein Hashmashos from letter of the law marked only the night although it is proper to be stringent to prohibit both the day and night]; Chavos Daas 184:5 and Biurim 8 [that after sunset is considered definite night]; Gr”a 184/11; Pardes Rimonim 184 Sifsei Chacham 5 that we follow nighttime; Chikreiy Halachos 2 on Admur ibid that according to Admur we follow nighttime regarding Vestos and when he wrote earlier sunset he really meant to nighttime and when he wrote Bein Hashmashos he really meant that one is unsure if the blood was seen before nighttime or prior to night; Tahraha Kehalacha 24:10 footnote 18 leaves this matter and doubt; Nitei Gavriel 85:10 writes that after sunset we only count the nighttime. Practically, the following opinions rule to count Bein Hashmashos as both day and night: Igros Moshe 4/15-1; Chikrei Halachos 2 chapter 184; The following opinions rule to count the five days from daytime: Shaareiy Tohar 16:1; Igros Moshe 4:17-20 is lenient up to 9 minutes after sunset; Ohel Sarah 2:1; Hagahos Imrei Baruchg 184; Taharas Habayis p. 407; The following opinions rule to count the five days from nighttime: Avnei Tzedek 85; Shiureiy Sheivet Haleivi 196:6 p. 296; See Tahraha Kehalacha 15:11 footnote 14-15 who leaves open the possibility to be lenient in a time of need up until nine minutes; See Nitei Gavriel 43:6 who writes that in a time of need one may be lenient

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