table and improve in quality during the game. The Soviets may attempt to slow German tank advances by flipping their small infantry divisions to create static fortifications (which double the combat value of another unit in the hex) and by using antitank brigades (which halve the value of attacking German armour). Another factor slowing the German advance into the USSR is the different railway gauge, which means that railroad lines in the USSR take longer to convert to German control. Air and Sea Warfare Each player has air factors, which may be used either for "air superiority" (fighting the enemy air force), or to enhance the die roll for ground combat, to suppress ports or to interdict hexes, making them harder to move through; the numerically-superior air force, after winning the air superiority combat, may largely prevent the enemy from conducting the latter functions. Whereas the German Luftwaffe might have ten or twenty factors during the invasion of France in 1940, by 1944 the Western Allies alone might have approaching 100 air factors, enough to interdict almost every hex in France. The Western Allies may also conduct a strategic bombing campaign, increasing in range and effectiveness as the war goes on, to bomb German industrial and resource centres (see below); the German player may attempt to fight this off with his own air factors and with flak units. The game also includes very rudimentary rules for naval evacuations (evacuated units are flipped to battlegroups) and seaborne invasions. Western Allied naval forces are not shown in the game apart from the landing craft needed for invasions, and these need to be used before most of them are withdrawn for the Pacific Theatre in the latter part of 1944. The German player may also build submarine and surface naval factors. Production The game places great emphasis on German and Soviet production; only German production is used in War in the West and only Soviet in War in the East (in each of these sub-games the German player must add or remove units to reflect historical transfers between the fronts). Once each month, the players spend production points to construct units, which are placed on giant production spiral displays to show how many months in the future they will become available – infantry units being available fairly quickly, with armour units taking longer, and air and naval units longer still. German production points