Q) What are the minimum number of bedikos during shivoh nekiyim that are essential?
A) 1) The Gemoro in Niddah quotes a machlokes between Rav and Rav Chanina regarding the minimum number of bedikos that are essential during shivoh nekiyim: Rav maintains that either a bedika on the first day or a bedika on the seventh day are essential; Rav Chanina argues that both are required – i.e. a bedika on the first day and a bedika on the seventh day are essential.
There is considerable debate in the Rishonim as to whether the halocho here is in line with Rav or Rav Chanina. The Beis Yosef quotes the major opinions among the Rishonim, and concludes that one should not be lenient, seeing as we are discussing a potential issur kores [i.e. we should follow the opinions who rule in line with the view of Rav Chanina and maintain that bedikos on both day one and day seven are essential].
The Shulchan Aruch quotes both opinions of the Rishonim; and concludes with the opinion of the Rishonim who rule in line with the view of Rav Chanina. Although usually when the Shulchan Aruch brings two differing views and presents them as “stam v’yesh…” we pasken like the former opinion; here the Shulchan Aruch himself concludes “v’ein l’hokel” – clearly ruling in line with the second opinion.
Therefore, a bedika on both the first day and the seventh day are essential; and shivoh nekiyim are invalid if these two bedikos were not performed.
It should be emphasized that we are only discussing a situation in which a hefsek tahara was successfully performed before shivoh nekiyim; if a hefsek tahara was not performed the shivoh nekiyim are invalid.
2) The Noda Bi’yehuda (Dogul Mervovo YD 196) presents a revolutionary understanding in the Rishonim who rule in line with Rav Chanina; namely, the emphasis of a bedika on both first and seventh day is only to facilitate that there should not be more than five complete days of shivoh nekiyim without a bedika. Consequently, if one performed a bedika on one of the intermediate days of shivoh nekiyim, and on day seven – shivoh nekiyim is still valid – because there has not been a time span of more than five days without a bedika (i.e. the time span between hefsek tahara and the first bediko, and the time span between the two bedikos of shivoh nekiyim).
However, many Poskim disagree with this leniency of the Noda Bi’yehuda and learn that day one and day seven mentioned in the Shulchan Aruch is specific and cannot be substituted with a bedika of another day. This is the general consensus of the Poskim.
In extenuating circumstances, or in an ex post facto situation – a sheiloh should be asked.
[44] ס”ח:
[45] יו”ד קצ”ו
[46] יו”ד קצ”ו סע’ ד’