Formally, there are sixteen stages — or contemplations — of
ānāpānasati. These are divided into four tetrads (i.e.,
sets or groups of four). The first four steps involve focusing the
mind on breathing, which is the 'body-conditioner' (Pali: kāya-sankhāra). The second tetrad
involves focusing on the feelings (vedanā), which are the
'mind-conditioner' (Pali: citta-sankhāra). The third tetrad
involves focusing on the mind itself (Pali: citta), and the fourth on 'mental
qualities' (Pali: dhamma). (Compare right mindfulness
and satipatthana.)
Any ānāpānasati meditation session should progress through the
stages in order, beginning at the first, whether the practitioner
has performed all stages in a previous session or not.[citation
needed]
