Rock Band studio Harmonix and parent company Viacom filed a suit in federal court in Boston against Konami Corp., alleging that the Japanese publisher's recent Rock Revolution violates a patent. The patent, issued to Viacom on December 2nd, claims that its guitar peripherals are "an improvement of earlier video-game controllers that emulate musical instruments," according to a report from financial website Bloomberg. Konami's Beatmania rhythm game series is cited in the patent as an example of older inventions. Rock Revolution's Xbox 360 and PlayStation 3 editions, developed by Zoë Mode and Savage Entertainment respectively, include a drumkit peripheral, but require that players use a Guitar Hero or Rock Band guitar controller for its bass and guitar portions. Released last October, Konami's Rock Revolution apparently sold poorly in its first month, according to NPD reports. Konami’s long-running Guitar Freaks and DrumMania series of titles feature similar gameplay to Rock Band, and also use musical instrument shaped controllers. This Viacom complaint continues a dispute that began after Konami filed a lawsuit in Marshall, Texas against Harmonix and Viacom in July 2008, claiming that Rock Band infringes two of its patents for simulated musical instruments, a music-game system, and a musical-rhythm matching game. According to patents examined by Gamasutra relating to Guitar Hero: World Tour, Activision's music game series now notably licenses Konami's patents, following an apparent patent pooling between the two firms -- leaving Rock Band the major holdout.