Ik Onkar opens both the Mul Mantar, the foundational statement of belief that begins the Guru Granth Sahib, Sikhism's scripture and living Guru, and the scripture's very first line, giving the symbol a textual position that few religious emblems anywhere can match: it is, quite literally, the first character a reader of the Guru Granth Sahib encounters.
W. H. McLeod's history of Sikhism reads the numeral one prefixed to the Gurmukhi character Onkar as making the theological claim explicit in the writing itself rather than leaving it to be inferred: there is exactly One Supreme Reality, not a highest among several, and the character functions simultaneously as scripture, as visual symbol and as the opening statement of doctrine in a single inseparable unit. The character's placement is not incidental to a manuscript layout convention: because the Guru Granth Sahib is treated in Sikh practice as a living Guru rather than only a text, the very first mark a reader or a congregation encounters when the scripture is opened for reading is this specific statement of divine oneness, giving the symbol a liturgical prominence that goes beyond its role as an opening line in an ordinary book. Devotional reproductions of the character, painted, embroidered or printed, are among the most common single images displayed inside a gurdwara and in Sikh homes, a prevalence that reflects its status as the tradition's core theological statement rather than one symbol among several of equal weight.