The Mishna Berura 188-16 mentions that if one is uncertain whether they mentioned ‘retzei’ (for the obligatory meals of course) they should repeat, because de facto they would not have mentioned it. If one does usually not eat bread during the week (or very seldom), to the extent that they bentsch (far) more frequently on Shabbos than otherwise, can one say that the chazakah would work the other way around and therefore if they were uncertain if they mentioned ‘retzei’ on Shabbos (for the obligatory meals of course) then they would not need to repeat? Any sources would also be much appreciated.
A related question: is the obligation to mention ‘retzei’ Rabbinical, and therefore if one forgot/left it out, then the requirement to repeat (if after having started enough of the fourth brocha) would be Rabbinical, but that on a Torah level they would have satisfied their obligation (provided they had eaten k’deis’viah)? If so, is there a nafka minah if the person initially was bentsching wasn’t satiated (with regards to the requirement to repeat) – one doesn’t seem to find such a distinction in the Mishna Berura.
- In order to change your nature you have to have bentched 90 times only on Shabbos (6-7 months) without eating a bread meal during the week. This is extremely uncommon. However if it indeed is applicable and this became his norm, then he would not have to go back.
- Interesting point, however it isn’t going to make a difference, and in both cases he has to recite bentching again. The reason is because we assume that he certainly didn’t say, and it isn’t even a doubt. Even if ritzei is rabbinical, this is part of what was instituted, that when we assume that it wasn’t said that he has to say it again.
M:B 188-16. Shar Hatzion ibid.