How to Win at Reversi: Corners, Edges and Mobility
To win at Reversi, think about corners and moves, not disc count. Corner discs can never be flipped, so take corners and stay off the squares next to an empty corner (the X- and C-squares), which hand them to your opponent. In the middle game, flip few discs and leave your opponent as few moves as possible; only the count at the very end matters.
A quick rules recap
Reversi (also sold under the brand name Othello) is played on an 8×8 board that starts with four discs in the middle, two of each colour. On GameLake you play the green lily pads and move first; Hop plays the pink lotus flowers.
- A move must trap at least one straight line of your opponent's discs (across, up and down, or diagonally) between the new disc and one of yours. Every trapped disc flips to your colour.
- If you have no legal move, you pass and your opponent plays again.
- The game ends when neither player can move, usually when the board is full. Most discs wins; equal counts are a draw.
Why disc count misleads you
Beginners flip as many discs as they can. It feels like winning, but discs change hands all game long, and a big flip usually gives your opponent more targets and more moves. Games are really decided by who runs out of good moves first. Strong players often have fewer discs than their opponent for most of the game and still win the final count comfortably.
So instead of "how many discs does this flip?", ask two questions before every move: does it give away a corner, and how many replies does it leave my opponent?
Corners: the squares that can't be flipped
A disc can only be flipped if it's trapped between two enemy discs in a line. A corner disc has no squares beyond it in any direction, so it can never be flipped. Better still, a corner lets you build a row of safe discs along both edges next to it. Take a corner whenever you can, and plan your moves so that your opponent is forced to give you one.
X-squares and C-squares: don't give corners away
The X-squares (b2, g2, b7 and g7) are the most dangerous squares on the board while their corner is empty. Put a disc there and your opponent often gets a line from the corner straight through it. The C-squares (the edge squares right next to a corner, like b1 and a2) carry the same risk along the edge, a little less often.
Once a corner is taken, its X- and C-squares stop being dangerous, and they're often good squares to fill. Late in the game, playing a C-square can also be fine if your opponent can't use it to reach the corner. When in doubt, check: after my move, can they play in the corner?
Mobility: flip less, leave fewer replies
Mobility is the number of legal moves you have. If your opponent has only one or two moves, they may have to play a move they hate, like an X-square. You squeeze their mobility by making quiet moves: moves that flip few discs, ideally ones surrounded by other discs rather than facing empty squares.
Discs that touch empty squares are called frontier discs. Every one of yours is a possible handhold for your opponent's next move, so try to keep your discs in a compact group with few empty squares next to them, and let your opponent own the long, open walls.
Edges: useful, but not automatically safe
Edge discs can only be flipped along the edge, which makes them harder to attack than discs in the middle. But an edge disc with empty squares on both sides can be trapped, and grabbing an edge early often costs mobility. A good edge move is one your opponent can't immediately attack from the other side, and that doesn't open a path to a corner.
Parity and the endgame
Near the end, the board breaks up into small pockets of empty squares. Whoever plays the last move in a pocket flips discs that can't be flipped back, so you want to finish pockets yourself. This idea is called parity: if neither player passes, the player who moves second gets the very last move of the game, and in general it pays to answer your opponent's move inside the same pocket and to leave odd-sized pockets where you can play last.
- Count the empty squares in each pocket before you choose one to play in.
- Prefer moves that leave your opponent with no good move in a pocket, or no move at all. A pass hands you an extra turn.
- With ten or so squares left, stop thinking about strategy and count: which move gives you the most discs at the very end?
Practise on GameLake
Play Hop on Easy, Medium or Hard, or a friend on the same screen. Easy only looks one move ahead and often gives away corners, so it's a good place to practise taking them. Medium looks two moves ahead, and Hard looks five moves ahead and plays the last ten squares perfectly.
Press Teach me for a hint at any point. Hop rings a strong move and gives the simplest reason for it: taking a corner, blocking one, avoiding a square next to an empty corner (orange ring), leaving you fewer replies, or, near the end, the exact winning margin he counted.
Frequently asked questions
What is the best strategy in Reversi?
Take corners, avoid the squares next to empty corners, and keep your opponent short of moves by flipping few discs in the middle game. Count discs only at the end.
Is it good to flip lots of discs in Reversi?
Usually not before the endgame. Big flips give your opponent more moves and more targets. Quiet moves that flip one or two discs are often stronger.
What are X-squares and C-squares?
X-squares (b2, g2, b7, g7) sit diagonally next to a corner; C-squares sit next to a corner along the edge. While that corner is empty, playing there often lets your opponent take it.
Who goes first in Reversi?
The dark side traditionally moves first. On GameLake, the green lily pads (you) move first.
Can Reversi end in a draw?
Yes. If both players have the same number of discs when nobody can move, the game is a draw.
Who invented Reversi?
Reversi comes from England in the 1880s. Two Englishmen, Lewis Waterman and John W. Mollett, each claimed to have invented it in 1883.