Udasis are usually celibate and renounce worldly cares, but still regard themselves as Sikhs. Anand Ghan (see below) believed that Baba Sri Chand was an incarnation of God, and the only successor of Guru Nanak. Ghan also believed in many Brahmanical-cum-Hindu ideas that the Sikh Gurus did not advocate. These included the theory of the incarnation of God, Brahmanic rituals and practices and the belief in the necessity of renunciation, the practice of austerities, asceticism and celibacy, though most cut their hair. These largely Vedantic, philosophical beliefs led them away from Bhakti (loving devotion of the divine) to a knowledge and meditation of the divine, such that there was a shift from a personal God to an impersonal reality. Although they believe in the Adi Granth and pay it great respect, they do not believe in the householder (grihasti) of the Gurus, nor the doctrines of Guru Panth and Guru Granth, nor in the accumulation of wealth and property. Furthermore Guru Nanak's definition of 'udas' was "to make use of all things in this world and not deem them one's own, but only God's property, and ever to possess a desire to meet Him in udas". (See Foundation, Evolution and Transformation of the Sikh Panth entries). Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sanatan-sikhism/26751-udasis.html History
The Udasis were founded by Baba Sri Chand (1494-1629), the eldest son of Guru Nanak. Udasi, from the root 'udas' means detachment, withdrawal from worldly life, solitary, sadness and grief, and so refers to one who renounces. Traditionally he is said to have opposed his father's appointment of Guru Angad as the second Guru, and so he started his own order. He lived a celibate life of renunciation and asceticism. During the seventeenth century the Udasis grew in number and were respected by the early Sikh Panth. Early Sikh records show that there were ten major Udasi orders.
During eighteenth century, the Udasis (not appearing as Khalsa Singhs) escaped the persecution of the Mughal rulers. Since they considered themselves as Sikhs, this naturally led them to look after the Sikh shrines in the absence of Khalsa Singhs and the Akalis/Nihangs (see separate entries). Here they performed a key role in keeping Sikh teaching alive. Anand Ghan, an Udasi scholar of the late 18th and early 19th centuries, wrote commentaries on the Adi Granth from a largely Hindu-Vedantic perspective.
The Mahants (those in charge of the Gurdwaras) of the nineteenth and early twentieth century, frequently claimed an Udasi descent, though their life style had considerably changed. The crucial juncture in Udasi history came in 1921 when a Mahant of Nanakana Sahib Gurdwara, claiming to be an Udasi, orchestrated the massacre of a large group of Akalis (see separate entry) who were seeking non-violently to reclaim the temple. Today they are seen as Sahajdhari or Sanatan Sikhs as opposed to Khalsa Singhs (see respective entries). Symbols
No distinct restrictions on hair; some wore it long and matted, others short. The matted hair symbolises their renunciation of worldly life. To this extent many go around naked and smear ash on their bodies, again symbolising their death to the world of family relations business and caste. Adherents
There were more than a dozen orders at the end of Sikh Rule in 1849. The number of establishments rose dramatically from the 1790s to the 1840s. They had more than 250 centres (akharas) spread across the Panjab and even beyond. In the 1891 Census 10,518 Hindus and 1,165 Sikhs returned themselves as 'Udasis'. (Census of India, 1891, Vol.XX and Vol.XXI, The Punjab and its Feudatories, by E.D. Maclagan, Part II and III, Calcutta, 1892, pp.826-9 and pp.572-3.) However, there are no official contemporary numbers, (see also the note at the end of the Explanatory Introduction). Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=26751 Headquarters/ Main Centre
There were four Udasi centres (akharas or dhuans) each controlling certain preaching areas. These were eastern India (with the main centre at Nanakmata), western Panjab and Kashmir, Malwa and Doaba.