The Yesod v'Shoresh ha'Avodah (Sha'ar ha'Kolel) relates, "The Arizal writes, 'In order to save one's self from Kares, one should stay awake the entire night, without sleeping at all, toiling in Torah until the morning. It is proper to learn a subject related to the sin he committed for which he is Chayav Kares. Each night that a person does this atones from one Chiyuv Kares.' It is customary to learn on such nights the Mishnayos and Gemara of Maseches Kerisus, and Musar works that enhance the fear of Hash-m.
"Many have the custom to learn in this manner during the period of the Yamim Nora'im and Shovavim-Tat (the weeks during which we read Parshiyos Shemos to Tetzaveh). It is also customary to learn this Tikun while standing up. Nevertheless, one may perform this Tikun at any time of the year, by sleeping a bit during the day so that he can stay up an entire night and learn in order to be saved from a Chiyuv Kares."
The Chafetz Chayim quotes these words in Likutei Halachos (beginning of Maseches Kerisus) and adds, "Learning Torah does more for the purification of the soul then any other Tikunim, as we are told by the Sefarim ha'Kedoshim. It is certain that if a person learns the entire Maseches which deals with Kares and the various ways to exempt oneself from it, especially if he knows it thoroughly, it will be a tremendous aid in purifying his soul."
Maseches Kerisus, like Temurah, has suffered from a large number of printers' errors and omissions in both the text of the Gemara and the text of Rashi, although not to the same extent as Maseches Temurah. The words that appear in parentheses in the Gemara are often words that Rashi suggests should be deleted from the text of the Gemara. The corrections that are listed in the margin of the Gemara in the name of "B'S" are from the Be'er Sheva (see later, "Acharonim"). The text of the Gemara on each page tends to be lengthy, especially in the first chapter, where the comments of Tosfos were not printed at the side of the Gemara.
Besides the usual commentary of Tosfos that is printed at the side of the Gemara (from the second chapter and onward), an additional commentary of "short" Tosfos (Tosfos Yeshanim) is printed at the bottom of the page (from 2a until 15b).
While the proper pronunciation of the name of the Maseches is "Kereisos" or "Kerisos" (the plural word for the noun "Kares"), it is commonly pronounced as "Kerisus."
RABEINU GERSHOM - as the printers of the Gemara point out (Kerisus 2a), Rav Betzalel Ashkenazi attributes this commentary to Rabeinu Elyakim bar Klonimus. Indeed, the Shitah Mekubetzes to Me'ilah, which frequently cites this commentary to Me'ilah, consistently calls it by that name. The ROSH (Teshuvos, Klal 81:11) also calls the author of the "Perush Rabeinu Gershom" to Bava Basra that is printed in our editions, "Rabeinu Elyakim ha'Levi." However, the Aruch (Erech "Aran," Erech "Oref") attributes the commentary on Bava Basra to Rabeinu Gershom (see Rav Elchanan Wasserman Hy'd in his introduction to Kovetz He'oros; see also Rav Ilan's preface to Shitah Mekubetzes to Menachos, and the introduction to Perush Rabeinu Elyakim to Yoma, footnote #18, and pp. 24-25). In the manuscripts of the Shitah Mekubetzes (of Rav Ilan, see (b) below), which cite this commentary in its entirety, the commentary is also attributed to Rabeinu Gershom (however, see Rav Ilan's preface, as noted above).
Whoever the author is, the following is clear: (1) It is likely that the same person authored all of the Perushei Rabeinu Gershom printed in the Vilna Shas (on Bava Basra and Ta'anis); (2) That author lived approximately at the time of Rashi or slightly before him; (3) Rashi appears to have had access to this commentary (see Introduction to Temurah I:b; for more about Rabeinu Elyakim and Rabeinu Gershom, see Introduction to Yoma II:1:a).
(Rav Elchanan notes that the RASHBA (Teshuvos 4:109), who did not have our text of Rashi on Kerisus, quotes a paragraph that is found nearly verbatim in the commentary of this author to Kerisus 12b, quoting as his source, "Rashi.")
Throughout most of the Maseches, the commentary to the text of each page appears on a later page. Nevertheless, it is easy to find the commentary to any particular page by looking at the line under the commentary for the correct page citation.
The SHITAH MEKUBETZES, an anthology of notes by Rishonim collected by Rav Betzalel Ashkenazi (the Rebbi of the Beis Yosef) frequently cites the comments of many Rishonim besides the "Gilyon," in contrast to the style of the Shitah Mekubetzes in Temurah, in which he cites very few Rishonim. Among the Rishonim that the Shitah Mekubetzes to Kerisus cites are Tosfos, the Rosh, Rabeinu Peretz, and Rabeinu Baruch. Many of the more lengthy paragraphs are printed in the "Hashmatos v'Chidushin" section of the Shitah Mekubetzes at the end of the Maseches.
Rav Yakov David Ilan printed the Shitah Mekubetzes from Rav Shlomo Adani's copy of Rav Betzalel Ashkenazi's notes. (Rav Adani, author of "Meleches Shlomo" on the Mishnayos, was a student of Rav Betzalel Ashkenazi.) According to Rav Ilan (in his preface), Rav Betzalel Ashkenazi prepared two separate manuscripts of his Shitah on Kodshim (some pages of both original manuscripts have been preserved in Hebrew University's National Library), and the one printed in the Shas is not the same one that Rav Adani copied (except for the end of Menachos, and all of Chulin, as the Vilna printers note at the end of the Shitah Mekubetzes on Midos). Rav Ilan's Shitah is printed in clear, block letters with Rav Ilan's own invaluable insights, and occasionally his edition of the Shitah Mekubetzes includes additions to that which is printed in the Gemaras. His printing includes the commentary of Rabeinu Gershom.
ASIFAS ZEKENIM - two commentaries (Birkas ha'Zevach by Rav Shmuel Kaidonover (R'SH'K', quoted often in the margin of the Gemara) and Mayim Kedoshim) that deal primarily with corrections of the text of the Gemara, Rashi, and Tosfos.
LIKUTEI HALACHOS - written in the style of the Rif, the Chafetz Chayim compiled a collection of the Gemara's conclusions along with Rashi-style glosses and an additional commentary, called ZEVACH TODAH, in which he provides insights into the Halachos.
SEFAS EMES - short and penetrating insights by Rav Yehudah Aryeh Leib of Gur, the second Gerer Rebbe, grandson of the Chidushei ha'Rim (the first Gerer Rebbe).
MEROMEI SADEH - Chidushim on most of Shas by the Netziv (Rav N'aftali Tz'vi Y'ehudah B'erlin, great grandson of Rav Chaim of Volozhen), the last Volozhener Rosh Yeshiva. The Netziv's works include Ha'amek Davar on the Torah as well as well-used in-depth commentaries on the Sifri, Mechilta and She'iltos, responsa called "Meshiv Davar," and others.
CHIDUSHEI RABEINU HA'GRIZ HA'LEVI - the Chidushim of Rav Yitzchak Ze'ev Soloveitchik, the Brisker Rav. We strongly recommend the new printing of this Sefer (published by Mishor, 5754), in which the text is printed clearly with easily readable plain Hebrew letters, and all the comments on each Masechta have been combined and printed in their proper order (however, there still remain a number of very misleading printing errors that were not corrected). In Kerisus, this commentary reaches only until Daf 7a.
OLAS SHLOMO - a clear, Peshat-based commentary written on Seder Kodshim by Rav Shlomo Zalman Lipshitz of Horodno, 1910.
ARUCH LA'NER - a broad and penetrating commentary on the entire Maseches by the Rav Yakov Ettinger. He deals with all aspects of the Maseches with awesome sharpness, depth, and breadth.
BE'ER SHEVA - This early commentary (by Rav Yisachar Ber Eilenberg) is written on six Masechtos, with a collection of Halachic responsa. His commentary on Kerisus is called "Ner Hash-m." It covers the first and last chapters of the Maseches (for which the commentary of Tosfos had not been printed, in his days). He wrote his commentary in the style of Tosfos. The Acharonim discuss his words often, and references to his insights are often made in the margin of the Gemara.
ABIR YAKOV - by Rav Yakov Shimshon Shabsai Sinigalia of Ankona, Italy (~1750), author of the Shabbos Shel Mi on Maseches Shabbos and contemporary of the Chida. Reprinted by Ahavas Shalom in 1982.
AL MASECHES KERISUS - A collection of Acharonim called which includes NER TAMID (by Rav Baruch Bendet), KESER YESHU'AH (by Rav Moshe Betzalel Luria, the author of Sefer Nahor Shraga on Yevamos), and MENACHEM SHLOMO (by Rav Menachem Shlomo Gordon of Minsk; his commentary is on the Gemara and on the Tosefta of Kerisus).
PEIROS TE'ENAH - insights and explanations, culled primarily from the major earlier commentaries, written by Rav Shmuel Rothchild.
KOLLEL IYUN HADAF - The Kollel's invaluable "Insights to the Daf" touch on many of the questions one is likely to ask on Gemara and Rashi, as well as Halachic clarifications and in-depth discussions on issues and Agados of the Masechta. Our helpful "Charts" and "Background to the Daf" make the Maseches much more approachable, with translations, Girsa notes, and introductions to concepts discussed on the Daf. Summarize what you have learned with our "Review Questions and Answers," enhance your learning with our "Outlines of the Daf," or, if you prefer Hebrew, review with "Galei Masechta," a concise Hebrew review of the Gemara, Rashi, and Tosfos. Ask the Kollel your questions on the Daf and receive clear, authoritative answers. Write to DAF@DAFYOM[I]CO.IL for more information.
YOSEF DA'AS - published by Kollel Iyun Hadaf, Rav Yosef Ben Arza's renowned Hebrew compendium on the Masechta is now printed in hard cover (with a copy of the Wagschal printing of the Gemara), and is also available online through D.A.F. This outstanding publication provides clear and concise exposure to the distinct approaches of the Rishonim to the Sugya, analyses of the Acharonim, inspiring insights of the masters of Musar and Machshavah, and summaries of the Halachic conclusions of the Poskim. A comprehensive review section is also included.