1940 ESSR postcard, Soviet rates, postage due, Torgu – Riga. Latvia

From December 6, 1940 Soviet rates were in effect, inland postcard cost 20 kop (Latvian SSR now inland). 15 s pigeon stamp actually had franking value of 18,75 kop (15 s x 1,25 exchange rate). Postage due in Riga 10 kop.