Tristhana Facts
Tristhana is a key concept in Ashtanga Yoga. During physical practice, we are to focus on three points: Bandha and/or Posture (depending on who you ask!), Breath (free breathing with sound), and Drishti (gaze point). These three form a tripod upon which to settle the mind's focus.
Tristhana aligns with three of the eight limbs of yoga: Asana (posture), Pranayama (breath control), and Pratyahara (withdrawal of the senses).
For a comprehensive exploration of Tristhana and some of the debates around traditional methods, I recommend reading Amy's article. She’s a wise and wonderful teacher at Meadowlark Yoga in Edinburgh, Scotland.