In theory, trying to figure out what parts of games are protected by copyright is a straightforward affair. The rules of a game – which can be thought of as the “idea” of the game – are not protectable by copyright. A specific expression of a game – basically anything not dictated by the rules – is going to be protected by copyright. In practice things can get a bit more complicated.
A recent court decision finding that a Tetris clone called Mino infringed on Tetris’s copyright illustrates how hard this can be.
Mino Was a Tetris Clone
It was undisputed that Mino was a clone of Tetris. In fact, Mino’s developers’ first step in making the game was to study up on intellectual property law to get a sense of what parts of Tetris were protected by copyright and which parts were not. The judge’s job in this case boiled down to drawing a line between the core rules of Tetris and whatever additional artistic flourish the makers of Tetris brought to the game.
Drawing this line is never an easy task. If you define the rules very broadly, then the original designer can use copyright to protect every version of the game. If you define the rules very specifically, then every part of the game becomes part of the rules and the original designer is left with no copyright protection at all.
Some Rules are Unprotectable
In this case, the judge seems to have erred on the side of defining the rules broadly. She described the unprotectable rules as:
“A puzzle game where a user manipulates pieces composed of square blocks, each made into a different geometric shapes, that fall from the top of the game board to the bottom where pieces accumulate. The user is given a new piece after the current one reaches the bottom of the available game space. While a piece is falling, the user rotates it in order to fit it in with the accumulated pieces. That object of the puzzle is to fill all spaces along a horizontal line. If that is accomplished, the line is erased, points are earned, and more of the game board is available for play. But if the pieces accumulate and reach the top of the screen, then the game is over.”
But Other Rules are Protectable
In fact, this is a reasonably good description of the general rules of Tetris. But it leaves a few things out that make up some of the elements that make Tetris Tetris. The judge finds that the shape of the Tetris blocks are not part of the rules. A designer can make a falling block game with any shape of block, but the blocks that are used in Tetris are owned by Tetris. The judge also finds that a 10×20 field in a falling block game is protectable by copyright and owned by Tetris. Other field sizes are fine, but stay away from 10×20.
It can be hard to tell why the shape of the block and the size of the playing surface are not part of the rules for Tetris. For serious Tetris players the shape of the blocks and the dimensions of the field are probably just as important as the size of a basketball or the distance of the foul line to the basket is for a basketball player. You could play another game with a giant round ball and a foul line 30 feet from the basket, but it would not be basketball.
Does it Matter if a Game Starts as a Videogame?
There is another element of the decision that really highlights how complicated this can be. In a thorough review of past case law, the judge refers to past video game cases that dealt with karate and golf games. In those cases, the courts had recognized that different karate games or different golf games would be similar because they would need to rely on similar elements. For example, all golf games are going to include golf courses, clubs, a golfer, and a wind meter, among other things that make the games “golf.”
The judge distinguishes Tetris from things like golf or karate games as “a unique puzzle game” that does not have “stock or common imagery that must be included.” It is hard to tell why Tetris is a “unique puzzle game” and golf is not a “unique ball hitting game.” Golf is different from polo, but both can be described as games that use a stick to hit a ball towards a goal. Similarly, Tetris is different from Snood, but both are games that involve lining pieces up to eliminate clusters.
Sports like golf have grown in part because the rules are part of the public domain and anyone is free to build a course and play however they want. Tetris is newer, but it has already spawned countless copies and variants. Just because we can identify the first instance of Tetris, that does not mean that it should necessarily get more protection than any other game or sport.
None of this is to say that Tetris should not have any protection, just that the protection that Tetris does have should not prevent someone else from playing a game that follows the rules of Tetris. As more games start their lives as video games (as opposed to on a playground) the fact that they arrive on our consciousness in a copyright-protectable wrapper should not mean that the games themselves stay out of the public domain.
For another example of what happens when people are free to make the rules of a game their own, check out this post about 3D printing a new board for Settlers of Catan.