Konami has filed a lawsuit against Harmonix and Viacom, claiming that their Rock Band game infringes on three of the company's patents related to instrument-based videogames. Apparently, Konami patented its inventions years ago after releasing their long-running Guitar Freaks and DrumMania series of titles which feature similar gameplay to Rock Band and also use musical instrument shaped controllers.

As part of the complaint filed yesterday, Konami is demanding cash compensation in addition to an order that would block Viacom and Harmonix from using the musical devices in its games. We'll see how this turns out for Rock Band and what'll it mean for Guitar Hero franchise as well – though Activision is rumored to have reached an agreement with Konami to license these patents. Interestingly, Konami is planning to release its own Rock Band-style title named Rock Revolution later this year.