The Kaiser's Navy is a book supplement for the Second World War at Sea game series, exploring the alternate history possibilities had Imperial Germany survived the First World War and continued its naval expansion plans. There are 210 die-cut and mounted playing pieces: 70 double-sized "long" ship pieces, including two massive aircraft-carrying zeppelins (and extensive rules for airships in the SWWAS series), and 140 standard-sized ones representing task forces, submarines, aircraft and smaller warships. The pieces represent many of the ships of the High Seas Sea Fleet: modernized older dreadnoughts, modernized versions of the ships not completed, and some of those planned or discussed but never built. There are also two dozen new scenarios, or separate game situations, based on battles that might have been waged by the Imperial German Navy in the North Atlantic and North Sea. This module is not playable by itself, but requires ownership of Bismarck and Bomb Alley to enjoy most of the scenarios, and Arctic Convoy and East of Suez to enjoy them all.