In World War I, the Russian anti-communist Army of the Northwest used its own stamps under General Nikolai Yudenich during the Russian civil war.
The stamps were in fact Russian postage stamps with the Cyrillic overprint ‘Сѣв.Зап. Арміж’, referring to Северо-Западная арміж (“Northwest Army”). Fourteen different stamps were overprinted by the Army of the Northwest this way, ranging from 2 kopecks to 10 roubles.