Minchah on Rosh Hashanah begins with Ashrei and U'Va L'Tziyon, followed by the Torah reading [if it is Shabbat] or by the Amidah which is similar in form to that said at the morning service. After the cantor's repetition, Avinu Malkenu is recited unless it is either Friday afternoon or Shabbat, in which case Avinu Malkenu is omitted. In Sephardic communities, Avinu Malkenu is recited even on Shabbat.
After Minchah, the Tashlich prayer is recited [the "casting away" of sin]. It is customary to do this near a source of water - by the banks of a river or at the seashore. If there is no such source of water, Tashlich can be recited near a spring, cistern, or reservoir that contains rainwater. The following verse (Michah 7:18) is recited: Who is a G-d like You, Who bears iniquity and ignores transgression for the remnant of His chosen people! He does not retain His anger forever for He desires to be benevolent. He will again show compassion and will subdue our sins and cast all of their transgressions into the depths of the sea!
This is followed by additional verses of compassion from Scripture. Some communities add a special prayer composed by R. Chayim David Azulai [the Chida]. It is then customary to shake out one's pockets and the folds in one's clothing three times so that they are emptied, symbolizing the heart's intention to cast away sin and to be totally cleansed of transgression. A Scriptural allusion for this practice can be drawn from the verse (Nechemyah 5:13) that states: I too have shaken out my cloak, saying, Thus shall G-d shake out all those who shall fail to abide by this promise.
If the first day of Rosh Hashanah falls on Shabbat, in Ashkenazic communities Tashlich is said after Minchah on the second day; among Sephardic communities, Tashlich is always recited on the first day.
Click on the following links for text of the Tashlich prayers:
English Text | Hebrew Text