50 Roubles

The 1961 Soviet currency reform was a straight redenomination at 10:1 — every pre-1961 note worth ten roubles became one — introduced by Khrushchev's government partly to mop up black market cash hoards and suppress informal currency speculation that had flourished since the war years. The reform was announced with only weeks of notice, giving holders of large sums in old notes very little time to exchange amounts that might attract official scrutiny.

Goznak produced the entire 1961 series in Moscow, and the 50-rouble note remained in continuous circulation for three decades, outlasting the political order that created it — still technically valid when the USSR dissolved in 1991.