Shem HaMephorash

Shem HaMephorash (Hebrew: שֵׁם הַמְּפֹרָשׁ Šēm hamMəfōrāš, also Shem ha-Mephorash), meaning "the explicit name", was originally a Tannaitic term for the Tetragrammaton. Early sources, from the Mishnah to the Geonim, only use "Shem haMephorash" to refer to the four-letter Tetragrammaton. In the Rishonic period, the same term was reinterpreted to refer to a 42-letter name. In Kabbalah, it may also refer to 22 or 72-letter names, the latter being more common.

In addition to the Shem haMephorash, b. Qiddushin 72a describes a 12-letter name and a 42-letter name. By the start of the Rishonic period, the term "Shem haMephorash" could also be used for the 42-letter name, and this interpretation was retrojected into the Mishnah.

The medievals debate whether the 12-letter name is a mundane euphemism, unknown, YHVH-EHYH-ADNY (יהוה אהיה אדני), or YHVH-YHVH-YHVH (יהוה יהוה יהוה). Wilhelm Bacher and Adolphe Franck suggest that the 12-letter name was Chokmah)-Tevunah)-Da'at (חכמה תבונה דעת), but the doctrine of the Sefirot originated in the 13th century, roughly a thousand years after the 12-letter name was first described. A. Haffer suggests that it is אל יהוה אלהינו (El YHVH Elohenu) from Deut. 6:4.

Wilhelm Bacher and Adolphe Franck suggest that the 42-letter name was the full 10 Sefirot, but the Sefirot did not yet exist in Talmudic times. J. Goldberger argues that the 42-letter name was derived by gematriya, representing either אהיה אהיה or אלוה. Ignatz Stern wrote that it represents the names listed by Sifra d'Tziuta Ch. 4, winning the support of Ginsburg, but this passage is not even as old as the Zohar. Robert Eisler derives it from Ex. 34:6. A. Haffer suggests that it is יהוה אחד ברוך שם כבוד מלכותו לעולם ועד.

According to Maimonides and Rashi, the 42-letter name is unknown, but Rabbeinu Tam writes that it is "formed from 'In the beginning . . .' and the last verse" and Hayy ben Sherira says it is the acronym of the medieval piyyut Ana b'Koach, and Joshua Trachtenberg argues that Hayy's tradition may legitimately represent the Talmudic intent. although even Hayy did not claim to know its pronunciation. According to Hayy,

Though the letters of the 42-letter name are known, the pronunciation has not been [successfully] transmitted. Some say that it begins אַבְגִיתַץ ʾabgîtaṣ while others say that it begins אַבַגְיְתַץ ʾabagyǝtaṣ, and some say that it concludes שְׁקוּצִית šǝqûṣît while other say that it concludes שַׁקְוַצִית šaqwaṣît, and there are many more disputes besides which none can resolve.

Solomon ibn Adret (1235-1310) records that:

Different places have different pronunciations [of the 42-letter name]. Some pronounce it as fourteen words composed of three letters each, while others pronounce it as seven words composed of six letters each. The scholars of this land [Spain] follow the latter method, and such is the tradition received from Hayy, but I heard that the scholars of Ashkenaz pronounce it as fourteen three-letter words. There are also differences between the letters of our version and those of Ashkenaz [...] as to what you say, that each three-letter word is pronounced shewa-patah, there is one word pronounced shewa-shuruq, which is the thirteenth: the shin with a shewa and the waw with a shuruq.