- Soyuz velikogo dela) is a 1927 Soviet silent historical drama film directed by Grigori Kozintsev and Leonid Trauberg about the 1825 Decembrist revolt.

These initials originally belonged to the fiancée of the man who lost the game, and throughout the film, their meaning changes multiple times, symbolizing different interpretations such as "Happiness Drives Fools," "The Union of Great Deeds," "Follow… Betray… Finish!"

Medoks, a cardsharp, declares the first interpretation of the initials to be "Happiness Drives Fools" and seeks to enter local society by asking the wife of General Vishnevsky for help.

She refuses, but when Officer Sukhanov arrives to arrest Medoks, the swindler shows him the ring, claiming it represents the "Union of Great Deeds."

Medoks, disguised as Colonel Sokovnin, approaches General Weissemar, who was involved in suppressing the rebellion, and proposes using the ring to lure imprisoned rebels into a trap.