This article is an excerpt from our Sefer
Buy me here or on Amazon.com
Yaleh Veyavo:  One recites Yaleh Veyavo within Birchas Hamazon on Rosh Hashanah.
Harachaman: By the Harachaman’s one recites the Harachaman for Yom Tov “Harachaman Hu Yanchileinu Leyom Shekulo Tov”. Afterwards one recites the Harachaman for Rosh Hashanah “Harachaman Hu Yechadesh Aleinu Es Hashanah Hazos Letovah Velivracha”. On Shabbos Rosh Hashanah one recites first the Harachaman for Shabbos and then the Harachaman for Yom Tov and then the Harachaman for Rosh Hashanah.
Meiyn Shalosh-Al Hamichya: One adds the following words when reciting the after blessing of Meiyn Shalosh on Rosh Hashanah: “Vezachreinu Letovah Beyom Hazikaron Hazeh”
If one forgot to recite Yaleh Veyavo:
Remembered after beginning the 4th blessing or after completing Birchas Hamazon: If one forgot to say Yaleh Veyavo in Birchas Hamazon and he already finished Birchas Hamazon, or remembered only after he already began the first word “Baruch” of the blessing of Hatov Vehameitiv, then if this occurred on the night of Rosh Hashanah [i.e. the night meal] one is required to repeat Birchas Hamazon. If however this occurred during the daytime of Rosh Hashanah [i.e. the day meal] then one has fulfilled his obligation, and Birchas Hamazon is not to be repeated.
Remembered after the blessing of Uvinei Yerushalyim, but prior to beginning Hatov Vehameitiv: All the above refers to a case that one already began the first word “Baruch” of the next blessing. If however one remembered to recite Yaleh Veyavo after completing “Uvinei Yerushalyim” but prior to beginning the first word of the next blessing, then in all cases [i.e. whether night or day meal] he is to say the following blessing:
ברוך אתת ה‘ אלקינו מלך העולם אשר נתן ימים טובים לעמו לשראל לזכרון את יום הזכרון הזה. ברוך אתה ה‘ מקדש ישראל
Rosh Hashanah that coincides with Shabbos:
In the event that Rosh Hashanah falls on Shabbos one is to say Ritzei and Yaleh Veyavo. If one forgot to say both Ritzei and Yaleh Veyavo and remembered prior to beginning the word Baruch then he is to say:
ברוך אתת ה‘ אלקינו מלך העולם שנתן שבתות למנוחה לעמו לשראל באהבה לאות ולברית וימים טובים לזכרון את יום הזכרון הזה. ברוך אתת ה‘ מקדש השבת וישראל ויום הזכרון.
If one forgot to say only Ritzei or only Yaleh Veyavo then he only mentions the additional blessing of the skipped part. If one already said the word “Baruch” or already finished Birchas Hamazon-see Q&A.
By the night meal if one forgot Yale Veyavo he must repeat Birchas Hamazon. By the day meal one does not repeat Birchas Hamazon.
General Q&A relating to Yaaleh Veyavo
What is one to do in the event that he does know the Nussach of the Bracha mentioned above?
If he does not know how the blessing begins and concludes then in such a case [if this occurred on the night of R”H] he must repeat from the beginning of Birchas Hamazon. [By the day of R”H he is simply to continue with the next blessing.]
What is he to do if he remembers to say Yaleh Veyavo in the midst of the Bracha of “Boneh Berachamav Yerushalayim”?
What is the law if one forgot to say “Vezachreinu Letova” in Meiyn Shalosh [Al Hamichya; Al Hapeiros; Al Hagafen]?
One does not have to repeat the after blessing. This applies even when reciting an Al Hagafen after Kiddush. If one remembered prior to reciting the concluding blessing of “Baruch Ata Hashem” some Poskim rule one is to retract and recite the addition.
What is one to do if one is in doubt in whether he said Yaleh Veyavo?
We assume that one did not say it. Hence in a case that he would be required to repeat Birchas Hamazon for omitting it [i.e. night of R”H] then in this case as well the same law would apply.
What is the law if on Shabbos R”H one said Ritzei but forgot to say Yaleh Veyavo?
If he said Ritzei and forgot Yaleh Veyavo, then if he remembers prior to saying Baruch of the fourth Bracha then he should say the extra Bracha for Rosh Hashanah. If however he already recited the word “Baruch” then if this occurred by the night meal of R”H he must repeat Birchas Hamazon, reciting also Ritzei [for a second time]. [If he forgot to say Ritzei this second time it is questionable whether he fulfills his obligation and it is thus best to wash again on a Kezayis of bread and recite Birchas Hamazon.]
What is the law if on Shabbos R”H one forgot to say Ritzei?
If one said Yaleh Veyavo but did not say Ritzei, or he omitted both Ritzei and Yaleh Veyavo, then if he remembers after saying “Baruch” of the fourth blessing, or after completing Birchas Hamazon, then he must retract to the beginning of Birchas Hamazon and recite both Ritzei and Yaleh Veyavo. [Seemingly this would apply even by R”H day.]
 Yosef Ometz 1066 [brought in Piskeiy Teshuvos 597/1]; Machzor Chabad and so was the Rebbe’s custom [Otzer Minhagei Chabad 155 and 159; Hamelech Bemisibo 1/239]; See Shaar Hakolel 34/14
Other customs: Some have the custom to omit the Harachaman of Yom Tov on Rosh Hashanah. [Noam Megadim 33b; Taamei Haminhagim 377]
 Current Nussach in Siddur Admur; Siddur Yaavetz; Yifei Laleiv 2/1; Kaf Hachaim 597/8
Chabad Custom: In certain prints of Siddur Admur the above Harachaman was printed while in others it was omitted. The Shaar Hakolel 34/14 writes that in the original Nussach of Admur this was omitted. He brings many proofs that argue against saying this Harachaman for R”H as why should it be different than the other Yomim Tovim. Especially being that some hold one is to fast on R”H. In Sichas 1956, 2nd day of R”, the Rebbe recited the Harachaman aloud and stated that he had asked the Rebbe Rayatz whether to enter it into the Siddur and was answered that the custom is to recite it silently. Practically however for some reason the Harachaman was placed in large letters in the Siddur. [See Glosses of Rav Raskin p. 381; Otzer Minhagei Chabad 156 -159] See Otzer ibid that the Rebbe Rashab omitted the Harachaman from one of the Siddurim printed in his time although he recited it silently. Practically the Rebbe recited the Harachaman out loud many years during the Rosh Hashanah Farbrengens and the congregation answered Amen. [Otzer ibid]
Other Customs: Some are accustomed to omit this Harachaman. [Shaar Hakolel ibid] Some are accustomed to recite this Harachaman throughout Aseres Yimei Teshuvah. [M”E 602/1] Others are accustomed to recite it until Simchas Torah. [Piskeiy Teshuvos 597 footnote 7] Some write that the Nussach is as follows: “Harachaman Hu Yechadesh Aleinu Shanah Tova Umetuka”. [Siddur Reb Shabsi]
 Piskeiy Teshuvos 597/1; See P”M 490 A”A 1
 Siddur Admur
 Siddur Admur [printed in Birchas Hamazon prior to the Bracha of Hatov Vehameitiv; brought in Alef Hamagen 584/29]; Unlike ruling in 188/10 that implies one is never to repeat Birchas Hamazon, neither by night or by day;
Ruling of Admur in Shulchan Aruch and other Poskim to never repeat: In 188/10 Admur rules as follows: “If one did not remember to recite Yaleh Veyavo on R”H and he already began the blessing of Hatov Vehameitiv then he does not repeat Birchas Hamazon being that [eating a meal and] reciting Birchas Hamazon on these days is voluntary, as if one desired he could eat fruits in order to avoid [the prohibition of] fasting. Furthermore, on R”H there are opinions that permit even fasting [and hence according to them repeating Bentching for Yaleh Veyavo is not allowed]. Now although we do not rule like their opinion [see 597/1] nevertheless one is to suspect for their opinion in order not to enter into a Safek Bracha Levatala if he were to repeat Birchas Hamazon.] From the fact Admur does not differentiate between the night and day meal implies that there is no difference and one may not repeat Birchas Hamazon at any time on R”H. The following Poskim rule as does Admur in 188/10 that one is never required to repeat Birchas Hamazon if he omitted Yaleh Veyavo by any meal of Rosh Hashanah: M”A 188/7; Kaf Hachaim 597/7; second opinion in M”E 583/4; Derech Hachaim brought in Alef Hamagen 584/29]
Ruling of Poskim to always repeat: Some Poskim rule that Rosh Hashanah has the same status as any Yom Tov meal of which one must repeat Birchas Hamazon if Yaleh Veyavo was omitted by the first two meals. Their reasoning is because according to the final Halachic ruling it remains forbidden to fast on Rosh Hashanah, and hence eating bread is an obligation as by all Yom Tov meals. [Elya Raba 188 [brought in M”B 188/19]; M”E 583/4 [brings both opinions and concludes “and the main opinion is like the first-stringent-opinion]; Sdei Chemed Mareches R”H 2/45] According to all one does not repeat Birchas Hamazon by a third meal eaten on R”H or when one is Bentching on Motzei R”H for a meal that was started on R”H day. [M”E ibid; Admur 188/15 regarding third meal; Siddur regarding sunset; Ketzos Hashulchan 47/3, 8 and footnote 9] See Piskeiy Teshuvos 584 footnote 3 that Rav SZ”A originally ruled that by night one is not to repeat while by day he is to repeat.
 Admur 188/9; Siddur ibid; Ketzos Hashulchan 47/3; Tehila Ledavid 188/4
Other opinions: Some Poskim rule one may still recite the added blessing [brought next] so long as he has not yet said the word “Hakeil”. [Chayeh Adam brought in M”B 188/23; In the Biur Halacha he leaves this ruling with a “Tzaruch Iyun Gadol” however implies that simply the words Baruch Ata, in his opinion, is not problematic.
 The reason: As all opinions agree that it is forbidden to fast on the night of R”H. It thus follows the same laws as any Yom Tov meal. [Piskeiy Hasiddur 115; Shaar Hakolel 34/11 “As how else would one be able to perform the Mitzvah of Kiddush, eating fatty foods brought in Nechemia and the eating of the Simanim brought in the Gemara. Hence one must conclude there is a difference between the night and day even according to the stringent opinion.”]
 The reason: As some opinions rule that it is permitted to fast on the day of Rosh Hashanah and one is hence not obligated to eat. [188/10; Piskeiy Hasiddur 115]
 Siddur ibid; Admur 188/10-11
The reason: Since the Biblical portion of Birchas Hamazon concludes with the blessing of Uvinei Yerushalayim and it is thus not such an interval to say it there. therefore the Sages instituted a blessing to be said if one forgot to say Yaleh Veyavo. [188/10]
Beginning and concluding with a blessing: The additional blessing instituted for R”H in a case of forgetting Yaleh Veyavo both begins and ends with a blessing. [Siddur ibid] However in 188/11 Admur records a dispute as to whether one is to also end with a blessing. Some [M”A 188/7] rule one does not conclude with a blessing [similar to Rosh Chodesh] Others [Mahril; Elya Zuta] however rule one does conclude with a blessing as R”H is a holiday that has a prohibition of Melacha just like any other Yom Tov [and is hence not similar to Rosh Chodesh]. Practically Admur concludes in parentheses (“although Safek Brachos Lehakel, nevertheless if one chooses to follow the latter opinion and conclude with a blessing he has not lost out. Furthermore on R”H one can say that everyone agrees one is not to swerve from the regular Yom Tov dialect which concludes with a blessing, as the Sages did not differentiate between the blessing of R”H and a regular Yom Tov as we see they did in other cases.) [ibid] Practically in the Siddur Admur wrote the dialect with a concluding blessing. So rules also Shaareiy Tziyon 188/15
 Siddur; omitted in 188/11
 188/14; Sefer Haminhagim p. 129 [English]
 188/8; Ketzos Hashulchan 47/3
 See Piskeiy Teshuvos 597/1
 M”A 208; Elya Raba 208/20; M”B 188/22; Mamar Mordechai 84; Kaf Hachaim 208/67
Other opinions: The Ketzos Hashulchan 47/3 leaves this matter in doubt, questioning that perhaps it is better to finish the blessing and say the additional blessing of R”H rather than make an interval with a verse in Tehillim of Lamdeini Chukecha in middle of prayer.
 M”B 208/58; See Ketzos Hashulchan 47 footnote 8
 Ketzos Hashulchan 47 footnote 8
 Mamar Mordechai ibid; Gloss in Chesed Lealafim 208/9 [brought in Kaf Hachaim 208/67]
Other Poskim: The Elya Raba ibid implies one is not to go back if he already said the words “Ki Ata Tov”. [brought in Kaf Hachaim ibid]
 M”B 188/16; Ketzos Hashulchan 47/5
 Admur 188/13-14; Ketzos Hashulchan 47/6; Sefer Haminhagim p. 129 [English]
 Ketzos Hashulchan ibid footnote 15
 See Admur 188/13-14; Ketzos Hashulchan 47/6 regarding a regular holiday.
 As although the opinion that rules one is to fast on R”H holds one is to fast even on Shabbos Teshuvah, nevertheless we do not find anywhere in Poskim that there is a difference between Shabbos Teshuvah and other Shabbosim in terms of a case that one forgot Ritzei. The same lack of differentiation can be said regarding Shabbos R”H that since the Poskim do not discuss what to do if one forgot Ritzei it seems that according to all one is required to repeat Birchas Hamazon as is the normal rule. This is in addition to the discussion of whether one is to fast at all on Shabbos R”H or if even according to the stringent opinion they agree that when R”H falls on Shabbos one is not to fast. [See Sdei Chemed Mareches R”H 2/7 for a dispute between the Lev Chaim and Yifei Laleiv; See Otzer Minhagei Chabad 154]
The reason: What remains to be understood is what is the reason for the difference in ruling between R”H and Shabbos R”H and Shabbos Teshuvah, as by all these days there are opinions that hold one is to fast and hence we should apply the rule of Safek Brachos Lihakel? Perhaps the explanation is as follows: On R”H itself there are opinions that hold one is to fast, which means that they hold the Sages never included R”H as part of the Holidays that require Lechem Mishneh and a meal. Hence according to them one who eats and Bentches cannot repeat it if he forgot Yaleh Veyavo, as R”H is not obligated in a meal. However on Shabbos, whether it be Shabbos Teshuvah or Shabbos R”H, even they agree that one is ideally obligated to eat a meal due to Shabbos, and it is only that due to R”H that one is to fast [according to those Poskim who hold one may fast on Shabbos R”H]. Thus one who did not fast and fulfilled the Mitzvah of eating a meal on Shabbos must repeat Bentching if he forgot Ritzei, as Shabbos requires him to eat a meal. This is similar to one who made a vow not to eat on Shabbos and nevertheless ate in which case certainly we would hold that Bentching must be repeated if he forgot Ritzei even though what he did was forbidden, as the prohibition was due to an external factor and not due to Shabbos. Vetzaruch Iyun. Another explanation: Perhaps even according to the opinion that holds one is to fast on R”H on Shabbos Teshuvah or Shabbos R”H they hold it is a mere choice and not obligation [so rules Sdei Chemed Mareches R”H 2/7] and hence even they agree one must repeat Bentching if he decided to eat and forgot Ritzei, similar to one who could have made a Taanis Chalom on Shabbos and did not do so.