Kabbolas Taanis Yochid
There is an obligation to be mekabel taanis yochid before shkia of the fast day
1. Is it meakev? In other words if one wished to fast that particular day (eg Shovevim or as a Teshuvah etc.) but forgot to be mekabel the taanis – should he still fast or does he need to postpone it? Is there any point saying it after nacht?
2. Whilst virtually all the Siddurim print (and printed) the nusach of “Bli neder” in the kabbolas taanis, both R Sh Zalman sz`l and Harav YY Fisher sz`l write that there is no point being mekabel a tanis without it being a nidrei mitzo and this is certainly a mistake. They claim one must omit these words. What is the Rav`s opinion in this?
Many thanks in clarifying these questions
1 Yes, it is מעכב to be מקבל תענית, see .תענית יב that without the kabalah by day it is not considered a taanis. The Levush [562:1] explains that a fast is like a korban which must be set aside and designated before it is brought. Without the kabalah one actually will be held accountable for causing himself suffering without purpose. See M”B there s”k 23 that he may still receive a kapparah as one who refrains from meat and wine for a kapparah,
2 While some Gedolim opposed saying bli neder, the source is found in the siddur Derech Hachaim of the Nesivos Mishpat, and in the siddur of the Shlah as well. It is also mentioned by the Mekor Chaim in the above siman.
See Kovetz Teshuvos 1:57 where Rav Chaim Kanievsky is brought defending this practice, see also Shevet Halevi 10:156.
Being that people are generally weaker in our times and may come to violate the prohibition of nedarim, it would seem proper to in fact say bli neder and rely on the above opinions.