[4] Bharata, the legendary author of Natyashastra, speaks about the nine primary emotions by which Rasa, the primary sentiment that appeals to poetic sensibility, is nourished; they are – rati ('enjoyment'), hāsya ('mirth'), śoka ('grief'), krodha ('anger'), utsāha ('enthusiasm'), bhaya ('fear'), jugupsa ('disgust'), vismaya ('surprise') and sama or śanta ('peace'), based respectively on nine navarasas ('primary sentiments').
Utsaha is a 'bhava' (emotional state) caused by Determinants such as absence of sadness, power, patience, heroism and the like, and is represented on the stage by Consequents such as steadiness, munificence, boldness of an undertaking and the like.
Atman alone, possessed of pure qualities such as knowledge, bliss etc., and devoid of enjoyment of imagined sense-objects, is the sthāyibhāva of śanta.
Yudhishthira considered counsel as being superior to the command over material resources and dignity, and Chanakya puts utsāha in the lowest position among these three powers.
[13] Aurobindo recalls to mind the combined working of the four great instruments of Yoga for gaining Yoga-siddhi or perfection in yoga, viz., śāstra i.e. the knowledge of truths, principles, powers and processes that govern self-realization, utsāha, the patient and the persistent action on the force of personal effort on the lines laid down by knowledge, gurū or teacher and kāla the instrumentality of Time.