Yiḥyah Qafiḥ (Hebrew: רבי יחיא בן שלמה קאפח also Yiḥyah ibn Shalomo el Qafiḥ) (1850–1931), known also by the affectionate name "Ha-Yashish" (English: "the Elder"), served as the Chief Rabbi of Sana'a, Yemen in the late nineteenth and early twentieth centuries. He was one of the foremost rabbinical scholars in Sana'a during that period, and one who advocated many reforms in Jewish education. He was also learned in astronomy and in the metaphysical science of rabbinic astrology, as well as in Jewish classical literature which he taught to his young students. 
Rabbi Qafih, in his youth, studied under Rabbi Yiḥya b. Yosef al-Qāreh, and received his ritual-slaughtering license from him in 1870. Although Rabbi Yihya Qafih served for only one year (1899–1900) as the Chief Rabbi of Yemen (Turk. Ḥakham Bāshī), he was a permanent member of the rabbinic court in Sana'a until his death, serving with the Chief Jurist and Rabbi, Yihya Yitzhak Halevi (d. 1932), whose signatures appear together in many of the court documents and responsa issued in the first quarter of the 20th century. In the late 19th century, he was the host to the Austrian Arabist and archeologist, Eduard Glaser, who conducted research in Yemen, and at the turn of the 20th century, he carried on a written correspondence with the Chief Rabbi of Ottoman Palestine in Jaffa, Rabbi Abraham Isaac Kohen Kook.
Rabbi Qafiḥ had served as one of the chief instructors in the city's largest seat of learning (yeshiva), held then in the synagogue known as Bayt Saleḥ, until a famine in 1905, resulting from a war with the Ottoman Turks, forced the closure of the yeshiva. In the spring of 1906, Rabbi Yihya Qafiḥ was confirmed by the ruling monarch as one of four representatives of the Jewish community in Sana'a, along with Harun al-Cohen, Yiḥya Yitzḥak Halevi and Yiḥya al-Abyadh. The document outlined the obligations of the Jewish community toward the Muslim State and the Poll Tax (Ar. al-jizya) assessed against every male 13 years of age and older. In 1909, he became the headmaster of a Jewish school built by the Ottoman Turks in Sana'a, known as al-Makktab He initiated many reforms in Jewish education, such as teaching arithmetic and geography alongside the Torah, and employing Turkish teachers in the school for teaching the Turkish language to Jewish youth. One of the failures of the school, according to Rabbi Amram Qorah, was that by teaching the Turkish language, their study of Hebrew suffered, seeing that the Jewish youth had less time to fully acclimate themselves to the rules of Hebrew grammar and to the finesse of the language. During this time, the controversy over the study of the Zohar worsened. After being incarcerated twice by Muslim authorities in 1914, being released only in Adar of 1915, Rabbi Qafiḥ regretted his earlier reticence in not speaking out against certain ills of the community. He began to be more vociferous about the people's neglect of Halacha for more mystical matters. It was around this time that he augmented the Dor Deʻah movement in Orthodox Judaism, to counter the influence of Lurianic Kabbalah and restore the rational approach to Judaism, such as is represented by the thought of Maimonides and Sa'adiah Gaon, and to encourage strict adherence to the Halakha as formulated in the Mishneh Torah. However, the innovations and textual readings enacted by Rabbi Qafih in his Beit midrash were the main cause for the schism in Sanaa's Jewish community, a schism that was fanned perpetually by "highly spirited youth." Since the Darda'im were interspersed in all the synagogues in Sana'a, the proprietors of those synagogues feared that this would lead to changes in their own rituals and customs, which they strongly opposed.
Rabbi Yiḥyah Qafiḥ was known to have "spent huge sums in order to recover manuscripts, even fragments of manuscripts of his [Maimonides'] works."
Ethnographer and historian, Shelomo Dov Goitein, gave a poignant description of the new movement in Yemen of which Hayyim Habshush was a member, and which movement in later years, after his death, had been further expanded under the charismatic leadership of Rabbi Yihya Qafih: “...He (i.e. Hayyim Habshush) and his friends, partly under European influence, but driven mainly by developments among the Yemenite Jews themselves, formed a group who ardently opposed all those forces of mysticism, superstition and fatalism which were then so prevalent in the country and strove for exact knowledge and independent thought, and the application of both to life.” This same movement would later be coined the name Daradʻah by Rabbi Yihya Yitzhak Halevi, a word which is an Arabic broken plural made-up of the Hebrew words Dör Deʻoh, which means "Generation of Reason."
The work for which Rabbi Qafiḥ is most well known is Milḥamot HaShem (Wars of the Lord, which takes the same name as earlier books) and which he began writing in 1914. In it he argues that the Zohar is not authentic and that attributing its authorship to the Tannaitic sage Rabbi Shimon bar Yochai is to besmirch him. Milḥamot HaShem maintains that the theology of Lurianic Kabbalah promotes the worship of Zeir Anpin (the supposed creative demiurge of God) and the Sephirot and, in doing so, is entirely idolatrous and irreconcilable with the historically pure monotheism of Judaism. This stance met with much opposition, and led the Rabbi to become engaged in a respectful correspondence with Rabbi Abraham Isaac Kook (the first Ashkenazi Chief Rabbi of British Mandate Palestine, who was known for his emphasis on mysticism). Rabbi Qafiḥ sent a copy of Milḥamot HaShem to Jerusalem in hopes of expediting its printing there, so that in the event additional objections would be raised he would have the opportunity to respond while still alive, but delays and a prolonged printing process resulted in his death soon after its printing and editing. Some contemporary Rabbis of the Haredi camp, such as Rabbi Chaim Kanievsky, have echoed condemnation of Rabbi Qafiḥ's work as heretical. Others, such as Rabbi Ovadia Yosef, have expressed disagreement with Rabbi Yihyah Qafih's work but maintained that such views are not heretical. Yet others, such as Rabbis Eliyahu Dessler and Gedaliah Nadel, and the Israeli rationalist philosopher Yeshayahu Leibowitz, expressed agreement and maintained that it is acceptable to believe that the Zohar was not written by Rabbi Shimon bar Yochai and that it had a late authorship. Already over 200 years ago the Noda Bihudah, in his sefer Derushei HaTzlach, argued that the Zohar is to be considered unreliable as it came into our hands many hundreds of years after Rashbi's death and it lacks an unbroken mesorah as to its authenticity, among other reasons.
Rabbi Qafiḥ identified a strong superstitious influence in Yemen which he saw as contrary to Orthodox Judaism. For example, his grandson Rabbi Yosef Qafih related one of many Yemenite customs for "חינוך הבית" whereby they would bake plain bread without salt and prepare "the table of appeasement." Inviting more than 10 children aged seven or eight who waited outside, they set the table, scattering thin-ash upon it; crumbled the plain bread into bits, placing them upon the table holding the ashes; and exited the kitchen stating, to the demons (Hebrew: שדים), "this is your portion." Shortly thereafter they would abruptly open its doors, whereupon the children bursted in, grabbing the saltless pieces and eating them. Rabbi Yiḥya Qafiḥ sharply opposed these minhagim being of the opinion that, in addition to the stupidity of the matter, they are Biblically forbidden because of darkhei haEmori.
A figure spoken of frequently in the esoteric works on Kabbalah, particularly in the Zohar, is what has come to be known as the "lesser countenance" (Aramaic: זעיר אנפין), or the Demiurge, which term and its usage is believed to have been of Gnostic church origin, although in later years was seen by the kabbalists as one of the angels in heaven associated with the emotive faculties of the soul and with the concept of "finite power." The same figure is also known in Latin writings as Microprosopus, derived from the Greek mikros small + prosopon face, and is said to have a father. Certain kabbalists allege that our prayers and our worship go unto the "lesser countenance", and that the world was created by him. To Rabbi Yehiya al-Qafih, such statements amounted to heresy, since there was none other but God who created the universe and unto whom all men and women are to pray.
In a letter addressed to Rabbi Avraham Isaac Kook, the chief Rabbi of Mandate Palestine, Rabbi Yihya Qafih argues effectually that such beliefs stand in contradiction to the Law bequeathed to us by Moses. He levels harsh criticism against the Zohar for its endorsement of heretical teachings, such as that of the "lesser countenance" (Aramaic: זעיר אנפין), as well as against the new kabbalists who claim that "lesser countenance" is our God and we are his people, such as described by Sefer HaBrit (Article 20, item # 15) and by Yosher Levav (page 4), and who allege wrongly that it was he who brought us out of the land of Egypt, and that his wife (who is Malkhut) was she who smote the Egyptians in Egypt and at the sea, while it was he who revealed himself unto Israel at Mount Sinai and gave to us his Divine Law. All these things, Rabbi Qafih alleged, should be expunged from our religion, since the import of the Torah is clear that only God, and God alone, had done all these things for Israel.
Of Rabbi Yiḥyah Qafiḥ's more famous disciples were Mori Yiḥya al-Abyadh who served as the Chief-Rabbi of Yemen (1932–1934) after the death of Rabbi Yihya Yizhak Halevi, and whose most memorable enactment was to erect two new gates at the far north-western extremity of the plain where the Jewish Quarter was built, in order to fix thereby the laws governing the carrying of objects from one domain to another (Eruv), and to prevent Muslims from entering the Jewish Quarter at night to purchase liquor; Rabbi Yosef b. Aharon Amar Halevi (1911–1988), who rose to acclaim in the land of Israel for having punctuated the entire Babylonian Talmud in the traditional manner in which words were pronounced in Sana'a, a work that took him twenty years to complete; and Yisrael Yeshayahu, a member of the Israeli Parliament in 1951, and co-editor of the historical book,Shevuth Teiman, in 1945.
Rabbi Yiḥyah Qafiḥ's grandson, Rabbi Yosef Qafiḥ, succeeded his grandfather in Yemen, and later in Israel, to become one of the foremost leaders of the Yemenite community. He published corrected and translated versions of texts (see his published works), including all of Maimonides’ Jewish works based on centuries-old manuscripts rescued and preserved by his grandfather.
- The exact date of death, according to Professor Aharon Gaimani, was the 11th day of the lunar month Kisleu, 5692 anno mundi, or what was equivalent to 2 November 1931 (see: Tehudah – vol. 30 (ed. Yosef Tobi), Natanya 2014, p. 83, note 1).
- Shalom 'Uzayri, Galei-Or, Tel-Aviv 1974, p.7
- Tehudah - volume 30, (ed. Yosef Tobi), Netanya 2014, pp. 48–54 (Hebrew)
- The following testimony is brought down by Rabbi Yōsef Qāfiḥ (Ketavim - Collected Papers, vol. 2, Jerusalem 1989, p. 861): "The city of Ṣan‘ā’ is built at the foothill of the mountain, Jabal Nuqūm, on its west side. On the top of this lofty mountain are the ruins of a not-so-large, fortified city which bore the name of Barāš, and which tradition avers used to be a Jewish city. When I visited there in 1937, I found a few remains of large stone walls still standing upon their ruin, as well as two ritual baths that had been carved out of the rock, and also the ruins of a synagogue with the compartment that once served as the Ark (Hekhāl). The walls were made of large stones, roughly eighty cm. and higher. I did not find there engraved stones with images or with writing. However, my grandfather (Rabbi Yihya Qafih) told me that when the well-known Jewish researcher, Eduard Glaser, visited Ṣan‘ā’ in 1882, and who visited also the same area, he informed him that there were Jewish inscriptions there from the year 900 of the Seleucid Era. That is to say that in anno mundi 4349 (589 CE) Jews were already living in the town of Barāš."
- Shmuel Yavne'eli, Masa Le'Teman, Tel-Aviv 1952, pp. 187–188; 196–199 (Hebrew); Shalom ben Yiḥya Qoraḥ, Iggeret Bokhim, Beth Shemesh 1963, p. 18 (Hebrew). One of Rabbi Qafih's students who would later rise to prominence in Israel, Member of Israeli Parliament Yisrael Yeshayahu, published exchanges of correspondence between Rabbi Qafih and Rabbi Kook in his book, Shavut Teyman, Tel-Aviv 1945, pp. 212–222 (Hebrew)
- Shalom Gamliel, The Jews and the King in the Yemen, vol. 1-2, pp. 19-20, Jerusalem 1986 (Hebrew)
- Yalqut Teiman, Yosef Tobi and Shalom Seri (editors), Tel-Aviv 2000, p. 69, s.v. דרדעים (דראדעה) (Hebrew) ISBN 965-7121-03-5
- Amrah Qorah, Sa'arath Teiman, Jerusalem 1988, p. 70 (p. 83 in PDF) (Hebrew)
- Shalom ben Yiḥya Qoraḥ, Iggeret Bokhim, Beth Shemesh 1963, p. 17 (Hebrew)
- Yehiel Hibshush, Shenei Ha-meoroth, Tel-Aviv 1987, p. 199 (Hebrew)
- Shelomo Dov Goitein, The Yemenites (History, Communal Organization, Spiritual Life), Ben-Zvi Institute, Jerusalem, 1983, p. 305 (Hebrew).
- Rabbi Yosef Kafach - A Life Fulfilled by Matis Greenblatt
- Travels in Yemen (חזיון תימן, רויא אלימן ), Hayyim Habshush (ed. Shelomo Dov Goitein), Jerusalem 1941, p. 7
- Shalom 'Uzayri, Galei-Or, Tel-Aviv 1974 (Hebrew), p. 15
- Tohar Hayiḥud - The Oneness of G-d in its Purity p. 40.
- Shalom ben Yiḥya Qoraḥ, Iggeret Bokhim, Beth Shemesh 1963, p. 18 (Hebrew)
- Tshuvos Derech Emunah , p. 30.
- שאלות ותשובות מעין אומר חלק א, chapter 7, siman צג.
- An Analysis of the Authenticity of the Zohar (2005), p. 39, with "Rav E" and "Rav G" later identified by the author as Rabbi Eliyahu Dessler and Rabbi Gedaliah Nadel, respectively (Rabbi Dr. Marc Shapiro in Milin Havivin Volume 5 , Is there an obligation to believe that Rebbe Shimon bar Yochai wrote the Zohar?, p. יב [PDF page 133]):
"I approached Rav A [Aryeh Carmell] with some of the questions on the Zohar, and he responded to me - 'and what about nikud? Nikud is also mentioned in the Zohar despite the fact that it [is] from Geonic times!' he said. I later found this comment in the Mitpachas Seforim. I would just add that not only is nikud mentioned, but only the Tiberian Nikkud - the norm in Europe of the middle ages - is mentioned and not the Yerushalmi nikud or the Babylonian one — which was used then in the Middle East, and is still used by Yemenites today. Also the Taamay Hamikrah - the trop - are referred to in the Zohar - only by their Sefardi Names. Rav A told me a remarkable piece of testimony: 'My rebbe (this is how he generally refers to Rav E [Elijah Dessler]) accepted the possibility that the Zohar was written sometime in the 13th century.'"
"Rav G [Gedaliah Nadel] told me that he was still unsure as to the origin and status of the Zohar, but told me it was my absolute right to draw any conclusions I saw fit regarding both the Zohar and the Ari."
- In derush 25 which "had previously only appeared in a censored form" (Rabbi Dr. Marc Shapiro, Concerning the Zohar and Other Matters) in Derushei HaTzlach, Warsaw 1886 (Shapiro in Milin Havivin Volume 5 , Is there an obligation to believe that Rebbe Shimon bar Yochai wrote the Zohar?, p. ה [PDF page 126], footnote 13 [Hebrew]).
- In a portion of derush 25 first published by Yehoshua Mondshine in Or Yisrael, Nisan 5766, על חיבור הזוה"ק ותוספות מאוחרות שנשתרבבו לתוכו (Hebrew), p. 202 (highlighted by Shapiro in Concerning the Zohar and Other Matters). This portion (along with the remainder) was later published, from manuscript, by Dr. Maoz Kahana and Michael K. Silber in Deists, Sabbatians and Kabbalists in Prague: A Censored Sermon of R. Ezekiel Landau, 1770, Kabbalah 21 (2010), p. 355 (Hebrew).
- Yemenite-Arabic: מַידַת אַלנִיִיֵה. (Hebrew: שולחן הריצוי.) Compare Isaiah 65:11.
- Yemenite-Arabic: הַדֵ'א קַסמַכֻם. (Hebrew: זה חלקכם.)
- Hebrew original: שלדעתו נוסף לטיפשות שבדבר
- Halikhoth Teiman (1963), p. 202. See also Guide for the Perplexed, Part III, Chapter 46, footnote 22 in Rabbi Kapach's edition.
- Shevuth Teiman, Yisrael Yeshayahu & Aharon Tzadok, Tel-Aviv 1945, p. 216 (Hebrew), who brings down this teaching in the name of Shemuel b. Yosef Adeni, author of Naḥalath Yosef, who brings down the teaching in the name of Sefer HaBrit. The concept is further explained in Rabbi Qafih's seminal work, Milhamot Hashem, chapter 30 (ל), page 37 (Hebrew).
- Shevuth Teiman, Yisrael Yeshayahu & Aharon Tzadok, Tel-Aviv 1945, p. 216 (Hebrew)
- Shalom Gamliel, The Jews and the King in the Yemen (היהודים והמלך בתימן), vol. 1, Jerusalem 1986, pp. 128–132 (Hebrew); ibid., pp. viii–ix (English)
- Singly and Together - Israel Yeshayahu -- ישראל ישעיהו - לחוד ויחד (ed. Avraham Wolfenzon), Tel-Aviv 1992, p. 23 (Hebrew).
- As opposed to, e.g., medical.
- Galei Or - Historical Chapters, by Shalom b. Hayim 'Uzayri, Tel-Aviv 1974 (Hebrew)
- Online text of Milhamot Hashem (Hebrew)
- Emunat Hashem Reply to Milḥamot Hashem by pro-Zohar Jerusalem rabbis. (Hebrew)
- תשובת דייני דחצצתא ירושלים ת"ו in his pamphlet עמל ורעות רוח וחרמות ותשובתם (Hebrew)
- Rabbi Aharon Qafeḥ, A Bundle of Letters in the Handwriting of Rabbi Yiḥye al-Qafeḥ (Hebrew)
- Rare photo of Rabbi Yiḥye Ibn Shlomoh al-Qafiḥ, pictured with Rabbi Yiḥye al-Abyadh
- A famous picture of Harav HaGaon Yihye Kafeh "hanging in R. Joseph Kafih’s house" and posted by Dr. Marc Shapiro (http://seforim.blogspot.com/2007/11/marc-b-shapiro-responses-to-comments.html footnote 38).
- An Analysis of the Authenticity of the Zohar (2005). Includes quotations of the views of "Rav E" and "Rav G," identified by the author as Rabbi Eliyahu Dessler and Rabbi Gedaliah Nadel, respectively (Rabbi Dr. Marc Shapiro in Milin Havivin Volume 5 , Is there an obligation to believe that Rebbe Shimon bar Yochai wrote the Zohar?, p. יב [PDF page 133]).