The Hirmos is a Hymn at the beginning of each Ode of the Canon. It dictates to the Troparia of the Ode their tone, general rhythm, and focus.

Basic Rule: For the Liturgy of St. John Chrysostom the Hirmos is "It is fitting and right to call you blessed, O Theotokos ...".For the Liturgy of St. Basil the Great "In you, O woman full of grace, all creation exults ..."

It is replaced by the Hirmos of the ninth Ode of the 1st.Canon of the Feast for first and second class Feasts. It is also replaced by the Hirmos of the ninth Ode of the 2nd.Canon of the Feast as follow:

• Leave-taking of first and second class Feasts
• The second Day of the Theophany of Our Lord
• The second Day of Pentecost
• The second Day of the Nativity of our Lord
• From Saturday of Lazarus to the Sunday of St. Thomas
• All Sundays of the Resurrection Period