When the Mishnah states what the Kohen Gadol would say during the Viduy, it
refers to the Name of Hashem not in the usual manner with the letter "Dalet"
as an abbreviation, but it says that the Kohen Gadol says in the Viduy
"ha'Shem" ('Heh' 'Shin' 'Mem'). The reason for this is because this Name is
different than the normal Name of Hashem. The Kohen Gadol used the Shem
ha'Meforash (the "ineffable Name") on Yom Kipur. This is why the Gemara
later (66a) says that everyone who would hear the Name of Hashem would bow
down. The Gemara (39b) says that the Kohen Gadol uttered the Shem
ha'Meforash ten times on Yom Kipur -- three times in each Viduy for three
Viduyim, and one more time when he selected the Se'ir of Hashem.
(a) The Gemara says that the Kohen Gadol mentioned the Name of Hashem ten
times on Yom Kipur. The TOSFOS RID (70a) asks that the Gemara in Sotah (38a)
says that in the Mikdash, the Kohanim would recite Birkas Kohanim with the
Name of Hashem as it is written. Since the Kohen Gadol also said Birkas
Kohanim on Yom Kipur, he said the Name of Hashem more than ten times!
This is a question only on the Rosh's opinion. If, however, he said the 42-
letter Name each of those ten times as Rav Hai Ga'on asserts, then it is no
question, because during Birkas Kohanim he would use the four-letter Name.
(b) The TOSFOS RID asks further that the Kohen Gadol would bless the people
with eight blessings after completing the Avodah on Yom Kipur (Yoma 68b). It
seems that for these blessings he also used the Shem ha'Meforash. The Gemara
in Berachos (63a) says that the people never said "Amen" in the Mikdash, but
rather they said, "Baruch Shem Kevod Malchuso...." The reason they said
"Baruch Shem" instead of "Amen" is presumably because the public blessings
in the Mikdash were said with the Shem ha'Meforash, to which the proper
response is "Baruch Shem" as our Mishnah says (RITVA in Ta'anis 16a, TZELACH
in Berachos 63a, MAHARSHA in Sotah 41a).
Since the Gemara says that in the Mikdash the people responded to "all"
public blessings with "Baruch Shem," it must be that these eight blessings
recited by the Kohen Gadol were also said with Shem ha'Meforash. According to the Rosh, this is problematic, because if so the Kohen Gadol used the
Shem ha'Meforash much more than ten times. It must be that these ten times
the Kohen Gadol used the 42-letter Name, while for all other blessings he
used the four-letter Name.
(c) The GEVURAS ARI (66a) points out that we find in the Mishnah that all
the people who heard the Shem ha'Meforash bowed down. However, we do not
find that they bowed down during Birkas Kohanim even though the Kohanim used
the Name of Hashem k'Kesivaso (Sotah 38a)! It must be that the Name for
which they bowed was the 42-letter Name, while the Name used in Birkas
Kohanim was the four-letter Name.
How will the Rosh respond to these proofs against his opinion? (a) The TOSFOS RID answers that there was no obligation for the Kohen Gadol
himself to participate in the Birkas Kohanim on Yom Kipur. Other Kohanim may
have performed the Birkas Kohanim, and thus the Kohen Gadol himself did not
recite the Name of Hashem an additional time.
The MIKDASH DAVID (24:2) answers that perhaps the Gemara that says that the
Kohen Gadol said the Name of Hashem ten times is referring to the period
*after* the times of Shimon ha'Tzadik. The Gemara (39b) says that after
Shimon ha'Tzadik passed away, they stopped saying the Birkas Kohanim with
the Name of Hashem. (The Tosfos Rid, who did not suggest this answer, is
following his own opinion on 39b that even *after* Shimon ha'Tzadik passed
away the Kohanim used the four-letter name k'Kesivaso in Birkas Kohanim.)
(b) RASHI (69b, DH b'Gevulin) writes that the Shem ha'Meforash was not used
for blessings except for those recited in the Azarah itself. It was not used
anywhere else on Har ha'Bayis outside of the Azarah. The eight blessings
said by the Kohen Gadol after the Avodah of Yom Kipur were said in the Ezras
Nashim (Yoma 69b) which does not have Kedushas Azarah, and thus those
blessings were not said with the Shem ha'Meforash, the four-letter Name of
Hashem as it is written.
The RASHASH points out that in the Ezras Nashim the people certainly did not
answer "Amen" but they answered "Baruch Shem," as the Gemara (69b) learns
from Ezra. We see that even where the Shem ha'Meforash was not used, they
still said "Baruch Shem!"ý
The CHONEN DA'AS explains that perhaps this point is the basis of the
Machlokes Rishonim here. Rashi says that the eight blessings were recited
without the Shem ha'Meforash and yet the people still answered "Baruch
Shem." He maintains that responding "Baruch Shem" is not dependent upon
hearing the Shem ha'Meforash in order to explain why the Kohen Gadol only
said the Shem ha'Meforash ten times. The other Rishonim, who say that the
Name used by the Kohen Gadol in the Viduy was the 42-letter Name, learn that
the Kohen Gadol did say the four-letter Name while reciting the eight
blessings in the Ezras Nashim, and that is why the people answered "Baruch
Shem." Thus the argument whether "Baruch Shem" depends on hearing the Shem
ha'Meforash depends on whether the Kohen Gadol said the 42-letter Name or
the four-letter Name in the Viduy.
The RITVA (39a,b), though, learns that the Kohen Gadol used the four-letter
name of Hashem during the Viduyim, even though he himself explains that the
Kohen Gadol used the four-letter name k'Kesivaso *wherever* Baruch Shem was
answered, i.e. even in the Ezras Nashim (Ritva Ta'anis 16a). How will he
explain why there were only ten mentions of the Shem ha'Meforash on Yom
Kipur?
The RITVA himself (Berachos 63a) and the RASHBA in Berachos quote the
RA'AVAD, who asserts that Baruch Shem was not answered, and the Shem
ha'Meforash not used, except in Tefilos. When making a Berachah on reading
the Torah, though, the normal Shem Hashem was used. If so, perhaps the eight
blessings of the Kohen Gadol, which were recited after he read from the
Torah, were not considered normal Tefilos, like Shemoneh Esreh, and did not
require the Shem ha'Meforash.
(c) Perhaps the people did not bow down during Birkas Kohanim not because
the Kohanim didn't use the Shem ha'Meforash, but because the Kohanim were in
the middle of blessing them and the blessing of Birkas Kohanim must be done
face to face, "Panim k'Neged Panim" (Sotah 38a). The people had to face the
Kohanim and thus they could not bow down. When the Kohen Gadol said the
Viduy, though, he was not blessing the people, so they could bow down at
that time.
It should be noted that according to TOSFOS Sotah 38b, the people indeed
*did* bow down even during Birkas Kohanim. And according to the Girsa of the
VILNA GA'ON, no proof may be adduced from the wording of the Mishnayos,
since he erases from the Mishnah (66a) -- based on the Girsa in the
Yerushalmi -- *any* mention of bowing down on Yom Kipur (just like the first
two Mishnayos (35b, 41b) makes no mention of bowing when the Shem Hashem was
recited, see Insights to Daf 66a).