The duo were actually unnamed when the original arcade game was initially released in Japan, although the names Hammer and Spike were given to them in the cabinet and promotional flyer produced by Taito for the overseas version. The names Billy and Jimmy Lee were first established in the Famicom/NES version of the first game and consequently used in other console versions and tie-in products, such as "The Original Sound of Double Dragon" soundtrack album, but were not actually used in the arcade versions until "". Billy Lee's name comes from a combination of Bruce Lee's last name with the first name of his character Billy Lo from the movie "Game of Death", while Jimmy is named after musician Jimmy Page.