The Gibson Guitar Corporation announced Thursday that it is suing major retailers that sell "Guitar Hero" games. The suit is part of an ongoing legal squabble between the instrument manufacturer and the makers of the popular music video games.

It was reported late Friday (March 21) that Gibson has also sued MTV, Harmonix and EA for allegedly violating a 1999 patent with last year's music game "Rock Band."

The "Guitar Hero" suit seeks to block Amazon, GameStop, Kmart, Wal-Mart, Target and Toys "R" Us from selling the games, according to an Associated Press report. The instrument-maker claims the games violate a 1999 Gibson patent for virtual music performances.

"Gibson Guitar took this action reluctantly, but is required to protect its intellectual property and will continue to do so against any other person in accordance with the law and its rights," the company explained in a statement issued Thursday.

The Gibson suit was filed on Monday and charges Activision (the developer of "Guitar Hero") with violating U.S. Patent 5,990,405: "System and method for generating and controlling a simulated musical concert experience." That patent describes a setup that would connect a guitar to a television and a "system interface" with the option to include a stereoscopic headset to create a virtual-reality concert experience. The term "video game" does not appear in the 5,000-word patent. (To read the patent and see images of Gibson's setup, go to the U.S. Patent Office's listing.)

On Friday, Gibson also announced that it was suing MTV Networks, Harmonix and EA, the publishers, developer and distributors of "Rock Band," respectively, for infringing on the same patent.

"Gibson Guitar had made good-faith efforts to enter into a patent-license agreement with the defendants in this case," reads a Gibson statement. "The defendants have not responded in a timely manner with an intent to enter into negotiations for a patent-license agreement.

"Gibson Guitar had no alternative but to bring the suit, and it will continue to protect its intellectual-property rights against any and all infringing persons."

MTV officials could not be reached for comment, but a Harmonix representative told Reuters that "This lawsuit is completely without merit and we intend to defend it vigorously."

Calls to Gibson and its legal counsel were not returned by press time, but the pair of lawsuits are clearly the latest salvo in a conflict that began earlier this year, when Gibson representatives contacted Activision privately to state that the games were violating the patent. Then on March 11, Activision filed suit against Gibson for damages, seeking a court judgment that "Guitar Hero" does not infringe on Gibson's patent.

Earlier this week, Activision reps told MTV News that Gibson's claims were without merit. George Rose, Activision's chief legal officer, stated: "While Gibson is a good partner and we have a great deal of respect for them, we disagree with the applicability of their patent and believe any objective analysis will reach the same conclusion. We are confident in our position."

The "Guitar Hero" suit may surprise the many fans who have played the game, because to do so requires holding officially licensed replica Gibson guitars. It would have seemed these two companies got along: The guitars for the first "Guitar Hero" games were modeled from Gibson SGs, the Xbox 360 version of "Guitar Hero II" included a replica Gibson X-Plorer, and the controller for "Guitar Hero III" is based on a Gibson Les Paul.

It seems, however, that Activision isn't interested in Gibson guitars appearing in future "Guitar Hero" games. A letter submitted as evidence as part of Activision's suit suggests that any Activision/Gibson guitar deal is dead. In fact, Activision claims that is the reason for Gibson's complaint.

In a March 10 letter to Gibson's attorney, Activision lawyer Mary Tuck wrote: "As I indicated previously, Gibson knew about the Guitar Hero games for nearly three years but did not raise its patent until it became clear that Activision was not [interested] in renewing the License and Marketing Support Agreement. Gibson's delay suggests that its infringement assertions are not being made in good faith, and it has provided no justification for its conduct."

For more on these suits, including Gibson's item-by-item chart alleging how "Guitar Hero" infringes on the Gibson patent, check out our Multiplayer blog.

[This story was originally published at 3:15 pm E.T. on 3.21.2008]