Take to the skies over southeast England during the turbulent Summer of 1940, as the outnumbered aircraft of the RAF fought a desperate struggle of survival against the onslaught of the near-invincible German Luftwaffe. "Black Cross/Blue Sky" is a historical wargame that allows players to assume the role of either a British or German pilot during the Battle of Britain.

The core game rules use a revolutionary system based on the Squadrons game system later revamped into the Blue Sky series of rules. Nominated for the Charles S. Roberts Award for best historical miniatures rules set in 1996, the rules have been refined and expanded from hundreds of players’ feedback. The result is a game system which allows a huge number of aircraft to be easily handled without the tedium of written orders. Multiple sets can be combined to allow large games that are limited only by the space provided by the players.

The game originates from "Squadrons: The Battle of Britain" written in 1994. As a result of the success of Squadrons demand for more aircraft appeared. The Blue Sky Series of games resulted in the new rules Red Sun / Blue Sky. This was done to normalize aircraft statistics across theaters of war by revamping the formulas for calculating plane statistics.

The resulting rulesets / expansions have been published:
Red Sun, Blue Sky - Pacific Theater (Main Ruleset)
Blue Sea, Blue Sky - Mediterranean Theater (Expansion)
White Star, Blue Sky - Daylight Bombing (Expansion)
Red Star, Blue Sky - Russian Front (Expansion)
Black Cross, Blue Sky - Battle of Britain (Re-implements the Battle of Britain and provides for cardboard planes). 2nd Edition of Rules
Lost Squadrons Black Cross, Blue Sky - Expansion for Black Cross.

All planes published in these modules are compatible and can be played against each other. Only the planes from the original Squadrons are incompatible. While it took 10 years to publish Black Cross the expansion rulebooks even mention the requirement to have the black cross rulebooks or red sun rulebooks to play.

While the cardboard planes are not available for the theater books the plane statistics are 100% compatible.

Games