An abstract strategy game is a game of pure skill with little or no theme. Both players see everything (perfect information), nothing is left to chance (no dice, no shuffled cards), and the result depends only on the players' decisions. Chess, Go, checkers, Hex, Connect Four and Quarto are classic examples. Wikipedia describes them as "strategy games with minimal or no narrative theme" where outcomes depend mainly on player choice.
About us: we make Quads, an independent game built on the same hand-your-opponent-the-piece mechanic as Quarto. It isn't affiliated with Gigamic or the makers of Quarto.
The five traits
Wikipedia's article lists the features most abstract games share:
| Trait | What it means | In Quarto |
|---|---|---|
| Perfect information | Little or no hidden information. Everyone sees the whole game state. | The board and every piece left are in plain view. |
| No luck | No dice, shuffled cards or random events in a pure abstract. | Nothing random at all. |
| Minimal theme | Any theme is decoration and doesn't change the rules. | No theme: just shapes and colours. |
| Discrete turns | Players alternate with clearly defined legal moves. | Place a piece, then hand one over. |
| Strategic focus | Skill comes from spatial reasoning, pattern recognition and planning. | Spotting lines and counting safe pieces. |
Pure, borderline and not abstract
The line isn't sharp, and people argue about the edges. Here's how the article sorts some familiar games:
| Category | Examples | Why |
|---|---|---|
| Pure abstracts | Go, Pente, checkers | No theme, no luck, no hidden information. |
| Themed but abstract | Chess, tafl games, Hive | A theme (armies, kings, insects) that doesn't change how the game works. |
| Borderline | Stratego | No luck, but the pieces' identities are hidden. |
| Not pure abstracts | Backgammon, pachisi | Dice add chance. |
Game theorists use a narrower term, combinatorial games: two players, perfect information, no chance. Chess, Go, Hex and Nim all qualify, and so does Quarto.
Impartial vs partisan games
One distinction is especially useful for understanding Quarto:
- Partisan games give each player their own pieces or moves. In chess you move only white or only black, and in Connect Four you drop only your own colour.
- Impartial games give both players the same options. What you can do depends only on the position, not on who you are. Nim is the textbook example.
Quarto is impartial, as Wikipedia's Quarto article notes: there's one shared set of 16 pieces, and either player could place any of them. That's what makes its central twist possible. Since you can't own pieces, the game hands the choice of piece to your opponent. Our math of Quarto page goes further.
Examples, by how you win
Abstract games are often grouped by their goal. Some well-known examples:
| Goal | Examples | Board |
|---|---|---|
| Line up pieces | Tic-tac-toe, Connect Four, Gobblet, Quixo, Quarto | 3×3 to 7×6 |
| Capture or checkmate | Chess, checkers | 8×8 |
| Control territory | Go | 19×19 (also 9×9, 13×13) |
| Connect two sides | Hex | Rhombus of hexagons |
| Race or reach a goal | Quoridor (reach the far side), Santorini (climb to the third level) | 9×9, 5×5 |
| Surround | Hive (surround the queen bee) | No board |
For games that feel closest to Quarto, see games like Quarto. For which of these have been worked out by computer, see which board games have been solved.
What makes a good one?
J. Mark Thompson, whose 2000 essay "Defining the Abstract" helped shape this debate, argues that a good abstract needs depth, clarity, drama and decisiveness, and that these qualities pull against each other. He also describes a good abstract game as "a 'family' of potentially interesting logic puzzles" (as quoted by Wikipedia).
Quarto is a neat example of that tension:
- Clarity: the rules fit in a paragraph, and the board is only 16 cells.
- Depth: 536 of the 1,820 possible groups of four pieces share a trait, so threats are everywhere and hard to track. See Quarto by the numbers.
- Drama: the game can turn on a single hand-off.
- Decisiveness: it's a draw with perfect play, but real games are usually decided. With the 2×2 square rule they're more decisive still: we measured it.
And Thompson's "family of logic puzzles" is literal in Quarto. Any mid-game position makes a puzzle, as our 12 Quarto puzzles show.
Where to start
- Shortest to learn: tic-tac-toe or Connect Four, then Quarto. Here's how those three compare.
- For two players with one phone: see two-player games on one phone.
- Right now, in your browser: Quads is free, with computer opponents at five levels.
Frequently asked questions
What is an abstract strategy game?
A game with little or no theme, no luck and no hidden information, where the result depends only on the players' decisions. Chess, Go, checkers, Hex and Quarto are examples.
Is chess an abstract strategy game?
Yes, usually counted as a themed abstract: it has a theme (armies and kings) that does not change how the game works, and no luck or hidden information.
Is Quarto an abstract strategy game?
Yes. It has no theme, no luck and no hidden information. It is also an impartial game, because both players use the same shared set of pieces.
What is the difference between impartial and partisan games?
In an impartial game both players have the same moves available in any position (Nim, Quarto). In a partisan game each player has their own pieces or moves (chess, Connect Four).