Kṛṣṇa introduces the mechanical technique of ‘Dhyāna-yoga’, which He will explain in detail in the next chapter. He describes a process of shutting out all external sense objects and fixing the vision between the two eyebrows. This is the practice of ‘Pratyāhāra’, or sensory withdrawal. The yogī then balances the upward and downward breaths (‘prāṇa’ and ‘apāna’) within the nostrils. This breath control, or ‘Prāṇāyāma’, is designed to calm the nervous system and the brain waves. By regulating the bio-rhythms of the body, the yogī creates a stable platform for the mind to focus inward. This is the ‘hardware’ approach to spirituality—using the body’s own mechanics to force a state of stillness. Kṛṣṇa mentions this to show Arjuna that there are many paths to the same center. Whether through active work or quiet meditation, the goal is to stop the mind from being a slave to the outside world.