|"Derecho de Entrega" means "delivery fee" and here's the story behind this very special stamp: Until 31 December 1930, Spanish postmen used to get 5 céntimos cash for every home-delivered cover, with the exception of covers coming from abroad. Then the General Post Office, trying to "simplify" this procedure, created a stamp for this "delivery fee". As of 1 January 1931, these five céntimos stamps had to be added to the regular franking of every cover sent within Spain. This, of course, meant a real raise of the inland postage fee for a single letter from 25 up to 30 cts.
When this new postal rate was definitely introduced on 1 August 1931, no appreciable quantities of 30 cts stamps were available in Spain and therefore the "Derecho de Entrega" stamps were used up as regular postage stamps until their total selling off; but only on domestic letters.
So within the 1st period, from 1.1.1931 to 31.07.1931, these stamps were used as a kind of "obligatory surtax" stamps but within the 2nd period, from August 1, they were declared regular postage stamp which could be used for all franking within Spain only. We can also find some usage of this stamp on letters going abroad; sometimes taxed but mainly without consequences for the addressee.
1) Correct usage during the first period on a single cover Engraver: Anonymus design of the F.M.N.T. | Lithographic printing | Sheets of 200 | Perforation: 11,5 (comb)
from Torremolinos (Málaga) ton Sevilla (6. JUL. 31)
2) Double incorrect usage during the first period from Oviedo to Germany
(23. JUL. 31) without being taxed. Foreign letter rate at that time was 40 cts.
3) Incorrect usage during the second period from El Toboso (Toledo) to the president of the
United States (23. AUG. 31). 30 cts U.P.E.A. rate to US. Taxed but obviously the fee was not
collected from the head of state.
First issued: 1 January 1931| Valid until: 31.07.1931 resp. 11.01.1935 | Control numbers: None | Total issued: Unknown
1) Correct usage during the first period on a single cover
Engraver: Anonymus design of the F.M.N.T. | Lithographic printing | Sheets of 200 | Perforation: 11,5 (comb)