The original Japanese title of the first Mega Man game was Rockman. Capcom released the game for the Family Computer, or Famicom, in Japan on December 17, 1987, using the Japanese title Rockman (ロックマン).
The name reflects the franchise’s musical wordplay. The hero was originally called Rock, and his sister robot was named Roll, together forming the phrase “rock and roll.” That naming pattern continued through many characters, including Bass, Forte’s localized name, and Proto Man, who is called Blues in Japan.
When Capcom prepared the game for North America, it changed the title from Rockman to Mega Man. The localization was not a separate sequel or remake; it was the same foundational game, with regional differences in text, presentation, and box art. “Mega Man” became the permanent English name for the character and series, while “Rockman” remained the Japanese branding.
A common mix-up is Rockman World, which is the Japanese name for the Game Boy spin-off series. It is not the title of the original Famicom game. The first game is specifically Rockman in Japan and Mega Man in English-speaking markets.