commentaries - Who was the author/compiler of the Ikkar Tosfos Yom Tov?

I've noticed when learning Mishnayos that with the more basic layouts consist of the Mishna and the commentaries of Rav Ovadia M'Bartenura and the Ikkar Tosfos Yom Tov.

It is known that Rav Yom-Tov Lipmann Heller was the author of the Tosfos Yom Tov but did he also write/compile the Ikkar Tosfos Yom Tov? If he didn't, who did?

Answer

Two editions of Mishnayot I have on hand¹ ascribe this commentary, the עיקר תוספות יום טוב, to R' Meshulam Katz.

This Geni page attributes Ikkar Tosafot Yom Tov to R' Meshulam Katz, and identifies him as the Av Beit Din of Lvov, who died there in 1810.

The text in the Geni page is apparently copied² from a pedigree record included by R' Katz' great^3-grandson, R' Yitzchak Amsel³, in books that he wrote or edited, including Kitzur Darchei Teshuva. Here is the complete text of the note there on R' Meshulam Katz:

בן הגאון הקדוש מו״ה משולם כ״ץ זצוקל״ה, בעהמ״ח קיצור תוספות יום טוב על משניות ופתחי נדה, ממלא מקום אחיו הגה״ק המקובל הנורא המפורסם מאוד בעולם׳ מו״ה יצחק אייזיק כ״ץ זצוק״ל׳ בעהמ״ח ספר הנורא ברית כהונת עולם׳ אב״ד דק״ק קאריץ, ואח״כ נתקבל לראב״ד דקי׳ק לבוב, ושם מנוחת כבודו, וזה נוסח המצבה שלו בבית החיים בלבוב : ״נפלה עטרת ראשינו ביום א׳ דחג הסוכות, ספדה תורה כי נפל נזרה, נצחו אראלים את המצוקים ונשבה ארון אלקים, הרב הגאון מוה״ר משולם כ״ץ, בן הגאון מו״ה יואל כ״ץ׳ מיחוסי כהונה עד אהרן הכהן, תנצב״ה״.

My translation:

[The author's great-great grandfather was] son of the holy genius, our teacher, Rabbi Meshulam Katz, ZTzVK"L⁴, author of Kitzur Tosafot Yom Tov on Mishna and Pitchei Nida, who took the place of his brother (the holy genius mystic, revered and very famous, our teacher, Rabbi Yitzchak Isaac Katz, ZTzVK"L, author of the revered book Berit Kehunat Olam) as Av Beit Din⁵ of the holy community of Korets and was later accepted as the Rabbi / Av Beit Din of the holy community of Lvov, which is where his honor was [laid to] rest. And this is the text of his headstone in the cemetery in Lvov:

The crown of our head fell on the first day of the festival of Sukkot. The Torah eulogized, for its crown has fallen. The angels have triumphed over the sages, and the Ark of God has settled down. The Rabbi and genius, our teacher, Rabbi Meshulam Katz, son of the genius, our teacher, Rabbi Yoel Katz, of those pedigreed to priesthood back to Aharon the Priest. TNTzB"H⁶

---

^{1. Horev Publishing House, Jerusalem, 1993; and Shay Lamora Publishing, Jerusalem.}

^{2. Unfortunately without attribution, but Hebrewbooks+Google cuts through such problems.}

^{3. Hungary and USA, 1894-1981.}

^{4. The memory of a righteous and holy person to be a blessing.}

^{5. President of the Court}

^{6. May his soul be bound in the bundle of life.}