Explanation:

 The etymological root of the word 'Chhau' is traced to the Sanskrit 'Chhaya' or shade, referring to the mask used by the dancers. Chhau dance is evidently a war dance. The steps and movements, the attack and defence, the performers, each holding a sword and shield.

Chhau dance is a genre of Indian tribal martial dance which is popular in the Indian states of Odisha, Jharkhand and West Bengal. There are three subgenres of the dance, based on its places of origin and development, Seraikella Chhau, Mayurbhanj Chhau and Purulia Chhau.