How to Beat the Reversi AI
ReversiAI's seven levels fail in different ways. Once you know what mistakes each one tends to make, the plan against it writes itself.
Which levels remember the games they lost
| Level | Remembers the openings it lost to |
|---|---|
| Beginner | No |
| Easy | No |
| Normal | No |
| Advanced | No |
| Hard | Yes |
| Expert | Yes |
| Master | Yes |
From Hard upward the AI keeps a record of the opening sequences of games it lost and steers away from them next time. The lower four levels start every game from scratch.
Beginner and Easy: no strategy needed, just don't give away corners
These two barely consider the shape of the board. Hold to two rules: never play an X-square, and take any corner you are offered. Easy prefers corners and edges, so it occasionally grabs a corner, but it never plans for one. As long as you do not hand corners over, you win.
This is the stage for learning the rules. Turn on the legal-move highlights and concentrate on seeing which directions flip.
Normal and Advanced: they make positional mistakes, wait for the corner
Normal and Advanced go for the move that flips a few extra discs right now, so they regularly play X-squares and C-squares. The recipe:
- Flip little and stay compact in the midgame, so their legal moves slowly shrink to the squares next to the corners.
- The moment one plays an X-square, take the corner. Do not get greedy elsewhere.
- Extend from the corner along the edges, build stable discs, and the endgame takes care of itself.
Beating Advanced consistently means you have absorbed the first four principles in the strategy guide.
Hard: it is not short-sighted, so win the midgame
Hard is not fooled by short-term gains and finishes endgames accurately, so neither waiting for a blunder nor an endgame comeback works. You have to build a mobility advantage in the midgame:
- Count the opponent's legal moves after every candidate move and prefer quiet moves (flip interior discs, create no new frontier).
- Squeeze its mobility towards zero. If every option is bad it still has to pick one.
- Before the endgame, make sure you are already ahead in corners and stable discs. In the endgame it will be more accurate than you.
Expert and Master: use the tools to learn, then vary your openings
Expert and Master judge positions on mobility and frontier discs as well as discs, and never play on a whim. For most players these levels are for learning rather than beating:
- The best-move hint (★) shows the recommended move in the current position. Decide your move first, then compare. The gap tells you exactly what you are missing.
- Undo (↩) lets you take back a mistake and try again; one game becomes several lessons.
One mechanism most players never notice: from Hard upward the AI remembers the opening sequences of games it lost and avoids repeating them in later games. The same trick will not work twice against Master, so prepare two or three different openings.
Does the AI cheat?
No. The AI sees exactly the board you see and follows exactly the same rules; it has no extra information. It is strong only because it never flips extra discs out of impatience. Which also means that once you stop being impatient, the gap closes faster than you would expect.
Frequently asked questions
Can the Master AI be beaten?
Yes, but it takes midgame mobility control and prepared openings. Master finishes endgames accurately and remembers openings it lost to, so one trick will not work twice.
Why is the AI so strong in the endgame?
From Hard upward it rarely makes mistakes in the endgame. The game has to be decided in the midgame.
Does the AI cheat?
No. It sees the same board, follows the same rules and has no extra information.
Does the best-move hint change with difficulty?
No. It gives the same quality of recommendation regardless of the level you are playing against.
Does the AI's memory carry over between levels?
No. Each of Hard, Expert and Master keeps its own memory of the openings it lost to, so beating Master with a line does not make Expert avoid it. The memory is stored in the browser you play in; switching to another browser or device starts it fresh.