A Texas court has ruled that game mechanics are not protected under U.S. copyright law.

DaVinci Editrice had sued Ziko Games over its board game Legend of the Three Kingdoms for allegedly copying the DaVinci game Bang!.

The two games are functionally identical, differing only in terms of art style and setting (Chinese history versus the Old West).

According to the court's summary judgement, Bang!'s game mechanics cannot be protected under copyright law, as they are not considered "expressive" in the way that artistic style and written content are.

Under U.S. legislation, the judgement states, "copyright law does not protect an idea; only its expression is protected."

"Unlike a book or movie plot, the rules and procedures, including the winning conditions, that make up a card-game system of play do not themselves produce the artistic or literary content that is the hallmark of protectable expression," it continues.

"Instead, the game rules, procedures, and winning conditions create the environment for expression."

On one hand, the ruling opens up developers to having clones produced of their games, as have been seen repeatedly on mobile platforms especially; clones of the likes of Flappy Bird, Threes, and Triple Town abound.

Conversely, the manner in which game mechanics can be protected - patents - have the potential to stifle innovation, as seen in the recently-expired Namco patent on loading-screen minigames.

With game development and distribution becoming more democratised, the issue of copyright and ownership is a significant one, with many more disagreements likely to arise in the future.

Note: Judge Judy did not preside over this case.