Sancai-glazed female riders of this type are unusual though not unknown. Compare with similar figures wearing long coats with wide lapels and elaborate top knots, such as the example sold in our Los Angeles Rooms, 4 December 1998, lot 23; the figure sold in London, 9 June 1987, lot 66, which may be the example illustrated by R.L. Hobson, The Eumorfopoulos Collection, London, 1925, Catalogue, vol. 1, pl. XXIX, no. 290; and two other riders, one female, most likely from the same tomb illustrated, ibid., pl. XXIX, nos. 288 and 289.
For a discussion on the depiction of women on horseback, see Virginia Bower, "Two Masterworks of Tang Ceramic Sculpture", Orientations, June, 1993, pp. 75-77, where various examples are illustrated.