What is the bija mantra for the Vishuddha Chakra and how should it be chanted?

The bija (seed) mantra of the Vishuddha Chakra is HAM (sometimes written as HUM, pronounced with a slight nasal resonance). To chant it: sit in a comfortable meditative posture, close your eyes, bring your awareness to the throat, and begin softly chanting HAM on the exhale, or repeating it mentally with each breath cycle. Feel the vibration in the throat and the resonance extending into the skull and chest. Traditional practice recommends 108 repetitions (one mala) with a focus on sincere intention to purify and open the throat centre.