Tachanun or Taḥanun (Hebrew: תחנון "Supplication"), also called nefillat apayim ("falling on the face") is part of Judaism's morning (Shacharit) and afternoon (Mincha) services, after the recitation of the Amidah, the central part of the daily Jewish prayer services. It is omitted on Shabbat, Jewish holidays and several other occasions (e.g., in the presence of a groom in the week after his marriage). Most traditions recite a longer prayer on Mondays and Thursdays.

On all days except Monday and Thursday (days when the Torah is read in the synagogue), Tachanun consists of three (in some communities two) short paragraphs. In most Ashkenazic synagogues, Tachanun begins with introductory verses from II Samuel (24:14), and then continues with Psalm 6:2-11, which King David composed - according to traditional sources - while sick and in pain. In the presence of a Torah scroll, this first paragraph is recited with the head leaning on the back of the left hand or sleeve (right hand when wearing tefillin on the left) as per Shulchan Aruch, Orach Chayim 131:1-2). The second paragraph, "שומר ישראל" ("Guardian of Israel") is recited seated, but erect (some communities only recite it on fast days). After this point, and following the words "va'anachnu lo neida", it is customary in many communities to rise, and the remainder of the final paragraph is recited while standing. Tachanun is invariably followed by "half kaddish" in the morning and by "full kaddish" in the afternoon.

Yitzhak Yedid (Hebrew: יצחק ידיד‎, born 1971) is an Israeli Australian composer of classical music and jazz pianist.

Yitzhak Yedid was born on September 29, 1971 in Jerusalem, Israel. His family immigrated from Syria. He studied at the Rubin Academy of Music and the New England Conservatory in Boston with Ran Blake and Paul Bley in 1997 and 1998. Yedid lives in Australia.

In 1999 Yedid released his first CD, Compositions for Solo Piano, for the Musa label. This led to an invitation to perform in Scandinavia as the guest of the pianist Michael Smith, and to a joint recital in Sweden with the pianist Roland Pontinen. In 2001, Yedid’s second recording, Inner Outcry, was released, also for Musa. Yedid was commissioned to compose the suite Tachanun for the opening of “The Third Stream” festival in Vienna, Austria, in 2002. This composition has been performed many times in Israel including at the Kfar Blum Chamber Music Festival.

Myth of the Cave was commissioned by German record label Between the Lines. It was released in 2002. The five-movement piece has been performed at festivals in Germany and Austria, at the Vancouver International Jazz Festival in Canada and at the Tel Aviv Jazz Festival in Israel. It is based on Plato's allegory of the cave, about cave dwellers imprisoned in near-darkness since birth whose sense of reality is distorted. One of them escapes to the outside world, reports on what he has seen and is put to death for his revelations.