Za means “sitting” and zen means “meditation”. In the Sôtô school, zazen is practiced without any particular meditation technique. The key is to release unnecessary tension and let the breath deepen while maintaining the tone of the posture and the attention of the mind.
It is then that the body and the spirit regain “their normal condition” as taught by Master Taisen Deshimaru.

“Listening and thinking is standing outside the door. Zazen means coming home and sitting in peace.” (Master Keizan, 1268-1325, co-founder of the Sôtô school)