The Imperial Japanese Navy (IJN) is a recurring antagonist organization from the 1940 series, based on the real navy which existed up until the end of World War II. Later Imperial Japanese Army was added into 1940 Series.
The Imperial Japanese Navy features prominently during the first two titles in the series, 1942 and 1943: The Battle of Midway, where they act as the antagonists. In both games, the player controls the Super Ace, a U.S. Navy pilot whose mission is to fight through the IJN's forces. Most enemy ships in these games carry the IJN's ensign on their wings.
Due to the controversy regarding the depiction of the Japanese as enemies (since the series was created by a Japanese company for a Japanese audience), later games in the series dropped the IJN in favor of using other organizations (Nazi Germany was used only one time in 1941: Counterattack) as the main enemy force, though many of IJN's fighters still appear on them. But in 1944: The Loop Master, Capcom reintroduced Imperial Japanese Navy in addition to Imperial Japanese Army.
- Making Japanese Forces as heroes and/or winners in the series titled 194X when the actual tide of the war turned during the year 1942 would've been subjected to even more controversies: Japanese government has already infamous reputation in Asia for distorting, downgrading, trivializing and revising history and their war crimes.
- There is another actual World War 2-based game featuring warplanes from both sides called Sky Destroyer from Taito. However, unlike Capcom's 194X Series, Sky Destroyer features IJN's Zero fighter as a protagonist and hero flying its way to destroy Allies' island fortress. (referenced heavily from Pearl Harbor Raid)