Well studied complex lithographic value with three separate dies, five plated printing stones A, B (Die I), C, D (Die II), E (Die III), the latter easily being the scarcest.
One key work on this subject is: The One Anna & Two Anna Postage Stamps of India 1854- 1855 Dawson L.E., F.R.P.S.L.: pp102: 1948 – Reprinted 1997. Also very useful pictorial plating references are readily available. An important new publication is, 'Ikanni Tales: A Study of the One Anna Lithographed Label of 1854-55 – G. Rohatgi, 2019'. A monumental almost encyclopedic work, particulalry authoritative in describing the many facets of the lithographic printing process itself.