DIE A (1900). 

These rouletted stamps were printed by Waterlow & Sons of London with a die engraved by Herbert Bourne. In sheets of 10x10.

 DIE B (1901). 

The main difference between the Die of 1900 and the Die of 1901 was the shadow above the head, that it was removed in the new die.

Chile Main Page.

• Carreras y Bulbena, J.R. Primeras emisiones de los sellos de Chile. Edit. José Monge. Barcelona, 1923.
• The "Hamilton" collection of Chile.
• Schindler, W. "Chile's Columbus heads - The taming of the beauties". Discovery vol.12 no.4 (48) October, 1994. pp. 865-870.
• Arteaga Lyon, M.A. "El Origen de los primeros sellos chilenos". El Mercurio, Oct.30, 1988.
• Fosbery, J. "Were the rouletted stamps of 1877 and 1880 ever forged?" 2pp.