Aani Uthiram, or Ani Thirumanjanam, is an auspicious day in the Tamil Month of Aani (June -July) and is dedicated to Lord Nataraja (Shiva). The word "Thirumanjanam" means Holy bath. The festival is observed on the Uthiram Nakshatram day. In 2013, the date of Aani uthiram falls on July 14th. It is believed that Lord Nataraja gives darshan in the months Ani and Margazhi. The Lord’s form demonstrates his five-fold functions: creation, preservation, destruction, concealment and salvation.

According to Nirad Choudhuri, Lord Shiva is the ‘Complete God’. In Hinduism (Oxford University Press, 1979), he quotes Bhisma’s reply to Yudhistra from Mahabaratha – ‘I am incapable of enunciating the attributes of Mahadeva, who is ubiquitous but nowhere visible; who is the creator of Brahma, Vishnu and Indra; whom all the gods worship; who transcends all natural phenomenon (Prakriti) and the Absolute (Purusha); whom the Rishis who have arrived at truth contemplate; who is indestructible, supreme, the Brahman himself...

It is popularly believed that it was on Aani Uthiram day that Lord Shiva appeared before Sage Manikkavachakar under a Kurundai Tree and offered upadesha (advice). Sage Manikkavachakar is the author of Thiruvachakam.

Special rituals and processions are held on the day at Nataraja Temple. In the holiest Siva temple at Chidambaram, Aani Thirumanjanam is the most important date in the annual calendar. In 2013, this falls on the night of 13th July – early 14th July morning, when abhishekam is performed.

This year, Smt. Desa Mangaiyarkarasi will give a discourse drawing on Siva Puranam and other literatures on Lord Siva and reflect on the lives of Manikka Vachagar, Nandanar, Sundarar and other great saints who have prayed in the temple.