Rhythm game or rhythm action is a genre of music-themed action video game that challenges a player's sense of rhythm. Games in the genre typically focus on dance or the simulated performance of musical instruments, and require players to press buttons in a sequence dictated on the screen. Doing so causes the game's protagonist or avatar to dance or to play their instrument correctly, which increases the player's score. Many rhythm games include multiplayer modes in which players compete for the highest score or cooperate as a simulated musical ensemble. While conventional control pads may be used as input devices, rhythm games often feature novel game controllers that emulate musical instruments. Certain dance-based games require the player to physically dance on a mat, with pressure-sensitive pads acting as the input device.
The 1996 title PaRappa the Rapper has been deemed the first influential rhythm game, whose basic template formed the core of subsequent games in the genre. In 1997, Konami's Beatmania sparked an emergent market for rhythm games in Japan. The company's music division, Bemani, released a series of music-based games over the next several years. The most successful of these was the 1998 dance mat game Dance Dance Revolution, which was the only Bemani title to achieve large-scale success outside Japan, and would see numerous imitations of the game from other publishers.
Other Japanese games, particularly Guitar Freaks, led to development of Guitar Hero and Rock Band series that used instrument-shaped controllers to mimic the playing of actual instruments. Spurred by the inclusion of popular rock music, the two series revitalized the rhythm genre in the Western Market, significantly expanded the console video game market and its demographics. The games provided a new source of revenue for the artists whose music appeared on the soundtracks. The later release of Rock Band 3 as well as the even later Rocksmith would allow players to play the songs using a real electric guitar. By 2008, rhythm games were considered to be one of the most popular video game genres, behind other action games. However, by 2009, the market was saturated by spin-offs from the core titles, which led to a nearly 50% drop in revenue for music game publishers; within a few years, both series announced they would be taking a hiatus from future titles.