The practice of ‘Ānāpānasati’ gradually leads on to the establishment of the “Four Foundations of Mindfulness” (Pāli, ‘Satipatthāna’).

“A monk, having gone to the woods, to the shade of a tree, or to an empty hut, sits down cross legged, holding his body erect, and setting mindfulness to the fore: mindfully, he breathes in; mindfully he breathes out.

“Breathing in long (breath), he discerns, ‘I am breathing in long’; or breathing out long, he discerns, ‘I am breathing out long.’  Or breathing in short, he discerns, ‘I am breathing in short’; or breathing out short, he discerns, ‘I am breathing out short…”

( Excerpt from the Ānāpānasati Sutta, Majjhima Nikaya no. 118 )

The Ānāpānasati Sutta lists steps to compose the mind and to make it tranquil, so that spiritual insights can arise.  The practice of Ānāpānasati  (mindfulness of breathing) gradually leads on to the establishment of the “Four Foundations of Mindfulness” (Pāli, Satipatthāna ).