Ans. According to Abhinaya Darpana, written by Acharya Nandikeshwara, there are four main forms of Abhinaya. They are - Aangika, Vaachika, Aaharya, and Saatvika.
Aangika Abhinaya is when the dancer expresses themselves using their entire body. It is the first form of Abhinaya that the viewers can see and experience feelings and emotions.
Vaachika Abhinaya is when the dancer uses speech to express emotions and feelings. In Kathak, the dancer can freely communicate with the viewers through Padhant. This is unique to Kathak as compared to other dance forms.
Aaharya Abhinaya is when the dancer uses external forms of decoration such as costume and make-up to bring forth the emotions and feelings from the audience.
Saatvik Abhinaya is the most subtle, yet the most powerful form of Abhinaya. It requires a dancer to be completely involved in the character and experience their emotions.
Together, the four forms of Abhinaya form ‘Chaturvidh’ Abhinaya.