haṃ kṣaḥ ma la va ra ya [pronounced: ham ksha ma la wa ra ya]
The ten letters of the root mantra of Kalachakra are:
- the visārga in kṣaḥ, which features as the cresent below the anusvāra
- the anusvāra in haṃ
- the vowel a, which is the "life" of the consonants.