My first graded banknote was a 'dos caritos' issued during the Mexican Revolution in Chihuahua and I promised myself that I would not attempt acquiring all the combinations of control letters, dates etc as there are more than a 1000 known.
As there is always an exception to every rule I had decided that if some of the interesting varieties appeared cheaply then I would snap them up and this note ticks that box.
It is still a 20 pesos note (S537b, M926f) with black scalloped Treasury seal and a new date/control letter combination (6-10-15; MIN-S) which was nice but it was the extra stamp that drew my attention. During the war the fortunes of the various factions embbed and flowed necessitating the issue of new, territory restricted, currency to pay the troops. The easiest way to do this was to revalidate captured existing notes rather than trying to print new ones and this note is an example of this.
Postcard depicting Nogales and the US border ca. 1915 (geo-mexico.com).
The seal was used from 28 May 1915 in Nogales, a small town in Sonora on the border with the US. The stamp is round, in violet ink, with an eagle in centre and ‘SECRETARIA PARTICULAR DEL GOBERNADOR DEL ESTADO DE SONORA’ around the edge. According to papermoneyofmexico.com this revalidation had nothing to do with Secretario Particular and the stamp was used as it was the only one available, there also seemed to be a shortage of ink as it is also known in green, blue and black suggesting issuing currency was critical and they used what ever was lying about..
Even more interesting are the initials above the MIN-S, these are RM and stand for Remigo Montoya who appears to have been quite a character. As an 'official' currency expert for the neighbouring state of Chihuahua he was arrested just across the border in Tucson, Arizona having been caught stamping $500,000 of potentially counterfeit notes as genuine. During the chaos of war he surprisingly seems to have escaped prison and even retained his tresury job - I am sure the investigation of the counterfitting operation identifying a number of Mexican government officials and influential Sonoran businesman had nothing to do with this.
I love it that every coin and note is the chance to learn something new.