This chapter surveys the practice known in Mediaeval Tantric sources from South Asia as mātṛkānyāsa, i.e. the imposition/placement (nyāsa) of the fifty letters (akṣara) of the Sanskrit syllabary (mātṛkā, śabdarāśi) onto the limbs of the (either physical or ‘subtle’) body of the practitioner. This practice, in its various conceptual, meditative, and ritual aspects, is well attested – as svaravyañjananyāsa – in Old Javano-Balinese textual sources of both Śaiva and Bauddha persuasion. Having contextualized this practice in the South Asian and Javano-Balinese Tantric traditions, I discuss the different varieties of impo- sition of the syllabary attested in Old Javanese texts, and pinpoint their analogies and differences with prototypical Sanskrit sources. Finally, I illustrate in table- and diagram-form the principal lists of correspondences between letters and bodily places that can be extracted from the relevant sources, trace them back to Sanskritic parallels whenever possible, and discuss the ways in which those parallels were re-configured along localized lines in both Java and Bali in the course of the centuries.