It has been recently demonstrated [J. Choi, K. Nielsch, M. Reiche, R.B. Wehrspohn, U. Gosele, J. Vac. Sci. Technol. B 21 (2003) 763] that quasi-monodomain porous alumina with 300 nm interpore distance can be obtained by means of a 500 nm periodic master stamp applying the guided self-organization process. In this article, a theory based on suppression of the field-enhanced oxide dissolution at a wedge is suggested to explain the preparation of highly-ordered porous alumina with an interpore distance having 0.6 times the lattice constant of the master stamp. In addition, the occurrence of triangular pores, which is observed during the growth of pores by guided self-organization, can be explained and will be discussed in detail. (c) 2004 Elsevier Ltd. All rights reserved.