There is no āsana like Siddhāsana, no kumbhaka equal, no mudrā like Khecarī, no laya comparable to nāda.

This verse establishes four supreme practices, one in each major category of Haṭha Yoga:

1. Āsana → Siddhāsana — The perfect posture for stability and meditation.
2. Prāṇāyāma → Kumbhaka — Breath retention, the heart of all yogic breathing.
3. Mudrā → Khecarī — The seal of “moving in space,” where the tongue turns toward the nasal cavity.
4. Laya → Nāda — Absorption in the internal sound, the method of dissolving the mind.

These four practices represent the backbone of Haṭha Yoga sādhanā. To master them is to master the complete system.

Laya means dissolution or absorption. It is the process by which the mind progressively dissolves until reaching the state of unity. Nāda (internal sound) is the most effective vehicle for this process, as will be developed in the fourth chapter of the text.

This verse also functions as a map: it marks the highest peaks of each territory of practice.