Gemara

Mishnah: If Chazazis (blisters) came on the majority it is Pasul.

Rav Chisda: This is only if it was in one place. If it was in two or three places it is Kosher.

Objection (Rava): This is unreasonable! If it was in two or three places it is like Menumar (spotted), which is Pasul!

Correction: Rav Chisda taught about the Seifa.

Mishnah: If Chazazis came on the minority it is Kosher.

Rav Chisda: This is only if it was in one place. If it was in two or three places it is like Menumar, which is Pasul.

Rava: On the Chotem (this will be defined) any amount disqualifies.

Rishonim

Rif: If Chazazis came on the minority it is Kosher only if it was in one place. If it was in two or three places it is like Menumar, which is Pasul. On the Chotem any amount disqualifies.

Question: The Reisha disqualifies Chazazis on the majority. What is the Chidush of the Seifa, that Chazazis of the minority is Kosher?

Answer (Ran DH Olsah): The Seifa explains the Reisha, that it is Kosher only if the Chazazos are contained within the minority. I.e., the Reisha refers to Chazazos on the majority of the Esrog, even if their area is the minority.

Ran (DH Aval): The Ra'avad says that Menumar disqualifies only if it is a color Pasul for Esrog, such as white, black or green like grass. Others say that it applies to all colors, for it is not Hadar.

Rambam (Hilchos Lulav 8:7): If Chazazis came on an Esrog in two or three places it is Pasul. If Chazazis came on the majority it is Pasul. If any amount came on the Dad, the small end from the Pitam emerges, it is Pasul.

Magid Mishnah: It is not Hadar, therefore it is Pasul even if it does not reach until the white (inside the Esrog).

Rosh (3:15): Rashi explains that Chazazis is like blisters. They can be felt; they protrude (above the surface). The Yerushalmi says 'the Pesulim are only on the first day. The majority is from one side; the Chotem is like the majority.' This means like our Gemara, that in one place the majority disqualifies, and in two or three places a minority disqualifies. Some explain that Chazazis on the majority of one side is Pasul. This is difficult, for the Mishnah connotes that only a majority of the entire Esrog disqualifies.

Beis Yosef (DH veha'Ran): The Ran learns that the majority of one side is Pasul.

Rosh (ibid.): The Yerushalmi seems to hold that Chazazis is like Chaser, therefore it is Pasul only on the first day. This is unreasonable. If it is like Chaser, any amount should disqualify! Rather, it is Pasul all seven days because it is not Hadar. Perhaps the Yerushalmi holds that even Hadar is required only on the first day, unlike the Bavli.

Rosh (18): The Pesul of Chazazis can become Kosher by peeling it off, if underneath it is the proper color.

Rosh (19): If Chazazis came on the minority it is Kosher only if it was in one place. If it was in two or three places it is like Menumar and it is Pasul. The Ra'avad disqualifies if the Chazazos are scattered over the majority of the Esrog, even if they comprise the minority of the Esrog. If the Chazazos are in the minority of the Esrog, e.g. on one side, it is Kosher. This is reasonable that two or three Chazazos in one place do not disqualify. However, the Gemara connotes that Menumar in two or three places disqualifies in the same case that it is Kosher in one place, in the minority of the Esrog. Perhaps we can say that two or three places resemble one, i.e. the Chazazos comprise the minority of the Esrog.

Rivash (brought in Beis Yosef OC 648 DH v'Zeh Lashon): We rely on the Ra'avad; the Rosh agrees with him.

Rosh (20): Rashi explains that the Chotem is Ovi Govho (the highest place where the Esrog is thick). From there it slopes towards the top. This is where people normally look (therefore we are more stringent about Chazazis there). Rashi connotes that the slope itself is not the Chotem, The Rif and R. Chananel mention the Chotem regarding the Pitam. This suggests that the slope is the Chotem. This is the practice, to disqualify from Ovi Govho to the top.

Question: The Rif and R. Chananel do not disqualify Chazazis on Ovi Govho, only above it!

Answer (Beis Yosef DH v'Ika): The practice is to be concerned for Rashi's opinion as well as that of the Rif. Alternatively, the Rosh means from Ovi Govho to the top, but not including Ovi Govho.

Ran (DH Omar): Some say that the Chotem is the 'crown' under the Netz (flower).

Poskim

Shulchan Aruch (OC 648:9): If Chazazis (this is like Chazazan, the Targum of Yalefes (a wart)) came on an Esrog in two or three places it is Pasul.

Beis Yosef (DH uv'Orchos): Some say that Chazazis is when the Esrog hardened because it was stricken. According to Rashi it is thin blisters unlike the warts found on our Esrogim.

Mishnah Berurah (35): It does not matter whether the Chazazos came before or after the Esrog was detached. The Chazazos must be raised above the surface.

Question (Kesef Mishneh, Hilchos Lulav 8:7): If two places disqualify, all the more so three! Why do the Gemara and Poskim say two or three?

Answer #1 (Mishneh l'Melech): In some places the Gemara asks questions like this. Elsewhere, it does not. Tosfos (Shabbos 60b DH Hashta) answers that the Gemara does not ask when it is clear that the same applies to even more.

Answer #2 (Taz 14): Surely, if a hair's breadth separates two Chazazos it does not look Menumar and it is Kosher. 'Two or three' teaches that we disqualify two when they are like three, i.e. they are as far apart as the outer Chazazos when there are three.

Note: This assumes that the Chazazos are the same size. The Taz does not specify the distance between Chazazos of different size that makes it Menumar.

Kaf ha'Chayim (65): Beis ha'Sho'evah says that even if a hair's breadth separates two Chazazos it appears Menumar and it is Pasul.

Shulchan Aruch (ibid.): In one place if it is the majority it is Pasul. If any amount came on the Chotem, it is Pasul. The Chotem is from where it gets narrower and slopes towards the top.

Kaf ha'Chayim (70): The Bi'ur Halachah says that l'Chatchilah one should be stringent to include Ovi Govho in the Chotem. In pressed circumstances one may be lenient even on the first day and bless. It seems that one should not bless, for Safek Berachos Lehakel.

Shulchan Aruch (10): Some say that it is Pasul in two or three places only if the Chazazos are over the majority of the Esrog. This is even if the area of the Chazazos is the minority of the Esrog.

Gra (DH Yesh): If the Chazazos are on the minority it is no worse than if the entire area they occupy was one big Chazazis.

Note: This is unlike the Taz (14, brought above) who says that alternation of color makes it Menumar.

Shulchan Aruch (ibid.): But if the two or three places are over the minority, e.g. they are all on one side, it is Kosher. Some disqualify even if they are the minority on one side.

Mishnah Berurah (42): The Poskim hold like the lenient opinion. However, if some of the Chazazos extend to the other side it is Pasul, for they span the majority of the circumference, even if they do not span the majority of the area (Magen Avraham 13).

Rebuttal (Chazon Ish 147:5 DH Safek): If lines are drawn connecting all of the Chazazos and the enclosed area is less than half the Esrog, this is considered the minority.

Bi'ur Halachah (DH she'Kulam): The Beis Meir leans to permit even more than three places if they are on one side. One may rely on this after the first day.

Kaf ha'Chayim (75): Some say that the latter opinion is stringent only for a minority close to half. In any case one should strive to find an Esrog without any Chazazis.

Shulchan Aruch (12): From the Chotem and onwards, i.e. from where it slopes towards the Pitom, Chazazis or any changed appearance of any size disqualifies.

Magen Avraham (16): At least two blisters are required to disqualify. It is Pasul only if they are visible when holding the Esrog.

Levushei Serad (34): He learns from the next Sa'if, which says that Chazazis is like blisters.

Mishnah Berurah (49): Many disagree with this. Even one blister is Chazazis, as long as it is visible without close scrutiny.

Shulchan Aruch (13): Chazazis is like blisters. They have substance and can be felt, for they protrude.

Terumas ha'Deshen (brought in Beis Yosef DH Kasuv bi'Srumas and Sha'arei Teshuvah 8): Even though Blat Mul (Chazazis) that comes from leaves and the tree is common, it is Pasul because it is not Hadar. The practice is to allow them even if they can be felt. Perhaps people rely on the Rosh, who cites the Ra'avad to allow a Chazazis that is a normal color of Esrog. Since these Blat Mul are common, they are considered the color of an Esrog.

Sha'arei Teshuvah (8): The Terumas ha'Deshen was unsure about this leniency, so one should be stringent if they can be felt, unless it is pressed circumstances.

Magen Avraham (21): We are concerned only for blisters due to the Esrog itself, not if they are due to thorns.

Bi'ur Halachah (DH Abuva'os): Bechori Yakov says that Chazazis is from rotting of the fruit, when attached or detached. This is common when it rests on thorns, for air does not reach there. Spots that come from being pricked are not due to rotting, so it is Kosher.

Rema: Therefore, Chazazis called Bla Mul (Bletelach) do not disqualify, for they do not protrude. Some allow them because it is considered a (normal) color of Esrog, since many are like this.

Mishnah Berurah (50): The latter opinion permits even if they protrude. The Acharonim are stringent in this case, unless it is pressed circumstances.

Shulchan Aruch (16): If it is black or white in one place, if it is the majority it is Pasul. In two or three places it is like Chazazis, even a minority is Pasul.

Kaf ha'Chayim (107): Perhaps this applies to all colors that are not colors of Esrogim, such as red.