Genpei ToumaDen is a beat 'em up arcade game that was released by Namco in 1986 only in Japan. It runs on Namco System 86 hardware. Over a decade later, the game was released in America as part of Namco Museum under the title The Genji and the Heike Clans (The game's name translates from Japanese as "Genji and Heike Clans Defeat Demon Story").
The player makes his way along a very strange landscape fighting enemies as they appear. The game offers three types of action: Small Mode (standard), Big Mode (standard, but with large characters and usually boss fights) and Plain Mode (viewed from an overhead perspective). Most stages have torii, which are used to transport the player to a different stage. On most stages featured in Side Mode and Plain Mode, there are multiple torii that can be entered which will lead to different routes on the map. In Big Mode, however, there is only one torii at the end of this type of stage.
The leading character is a historical Japanese samurai called Taira no Kagekiyo who fell in the Battle of Dan-no-ura (1185). In Genpei ToumaDen, he was resurrected and fights Minamoto no Yoshitsune and Saito Musashibo Benkei over the Imperial Regalia of Japan, as well as to defeat his enemy Minamoto no Yoritomo.
The game also features the Sanzu River, a place believed in Japanese Buddhism to separate "the current life" and "the afterlife", resembling the concept of Underworld or Hell. Therefore, some mythological characters like Emma-o, god of the Underworld, and Sun Goddess Amaterasu appear in the game.
The game was ported to Famicom and Sharp X68000 in 1988. While the Sharp port stays faithful to the original, the Famicom port was an RPG. (Wikipedia)