299. Forgetting Al HaNissim

44:16 If one forgot to say Al HaNissim while bentching on Chanukah or Purim, and he only remembered after saying God’s Name at the end of the blessing, he does not go back. Instead, during the HaRachaman prayers, one adds “May the Merciful One perform miracles and wonders for us as He performed for our ancestors in those days, at this season,” followed by “in the days of Mattisyahu…” or “in the days of Mordechai…” as appropriate. (An insertion during the HaRachamans might also be a good solution for those who forget Yaaleh v’Yavo in circumstances that do not cause them to repeat bentching – see Rema 188:7.) 44:17 If one was eating on Shabbos afternoon and he continued until it got dark, he still says R’tzei in bentching because he has not yet davened Maariv to end Shabbos. This also applies for yom tov, Rosh Chodesh, Chanukah and Purim: if one began eating while it was still day, he says the special text for the occasion even if he bentches after nightfall. If one started eating on the afternoon preceding Rosh Chodesh and he continued eating into the night, having at least an olive-sized portion of bread after dark, he says Yaaleh v’Yavo; similar rules apply for Al HaNissim on Chanukah and Purim. If one started eating Shabbos afternoon and continued into the night, and the next day is Rosh Chodesh, if he ate an olive-sized portion after dark, he would say both R’tzei and Yaaleh v’Yavo. Again, the same applies for Al HaNissim on Chanukah and Purim. Some authorities disagree with this course of action because it appears to be self-contradictory, so it is preferable to avoid creating the situation.