The Tsar's Navy is a Second World War at Sea supplement exploring the alternate history possibilities had Imperial Russia survived the First World War and continued its naval expansion plans. The supplement includes ten scenarios, or separate game situations, based on battles that might have been waged by the Imperial Russian Navy in the Black and Mediterranean Seas. The pieces represent the ships of the Black Sea Fleet: modernized older dreadnoughts, modernized versions of the ships not completed, and some of those planned or discussed but never built. This module is not playable by itself, but requires ownership of Bomb Alley, Arctic Convoy and Imperial and Royal Navy to enjoy all of the scenarios. The Tsar's Navy is sold exclusively via .pdf download.