'Maskirovka' is the Russian military strategy of deception, involving techniques to surprise and deceive the enemy. Lucy Ash looks back over its long history from repelling invading Mongols in the 14th Century, to its use to confound the Nazis in World War II, to the current conflict in Ukraine. Translated literally maskirovka means "a little masquerade", but it also points to strategic, operational, physical and tactical duplicity. When heavily-armed, mask-wearing gunmen - labelled the 'little green men' - took over government buildings in Crimea last year, was this a classic example of maskirovka in the 21st century? All nations use deception as a strategy in war, but Analysis asks whether any other nation has pursued guile as an instrument of policy so long and so ardently as Russia.