What is the name of the Zoroastrian prayer that begins 'Ashem vohu'?

The Zoroastrian prayer that begins “Ashem vohu” is called Ashem Vohu. Its Avestan name means roughly “righteousness is best” or “truth/order is best,” reflecting a central Zoroastrian ideal: asha, the principle of truth, justice, and cosmic order.

Ashem Vohu is one of four important Old Avestan manthras, or sacred utterances, associated with the Gathic layer of the Avesta. In the Yasna, it appears immediately after the Ahuna Vairya prayer and before Yenghe Hatam. It is also recited at the end of many prayers in the Khordeh Avesta, a collection of shorter devotional texts.

A common mix-up is Ahuna Vairya, another extremely important Zoroastrian prayer that precedes Ashem Vohu in the Yasna. The two are closely connected in liturgy, but they are distinct prayers. Ashem Vohu is especially notable for its brevity: its twelve Avestan words repeatedly emphasize righteousness, goodness, and spiritual fulfilment.