“I instruct you to note the movement in the abdomen, which is prominent and easiest to note while you are seated. The tightness and movement in the abdomen is the Air Element (vayo-dhatu). I instruct you to note the Air Element by saying mentally "rising, falling" in ordinary language.
Practitioners (yogi) who have respectfully followed this instruction have achieved deep concentration (samadhi) within seven days. Having achieved a pure mind (citta-visuddhi), many thousands of them can discriminate between matter (rupa) and mind (nama) with direct knowledge.
Moreover, there are many thousands who, by means of direct knowledge, can distinguish cause and effect and understand the nature of arising, passing away, impermanence (anicca), suffering (dukkha), and no-self (anatta).
When their insight-knowledge (vipassana-nana) is mature, they observe the process of phenomena as they appear to the Six Sensory Doors (dvara). Assuredly, there are many thousands of practitioners who have attained the perfect knowledge of insight (vipassana-nana), which is said to be the perfect knowledge of Magga and Phala.”
:)
Ref: p 46, Sakkapanha-sutta (ebook), Mahasi Sayadaw. Translation is mine.
