The first time I beat a strong Reversi opponent, I did it by owning fewer discs for most of the game, and that one idea changed how I play everything on this board.
What I cover
1. Stop counting discs
The single biggest mistake new players make is trying to hold the most discs the whole way through. In Reversi, only the count at the very end matters, and a big lead in the midgame is often a warning sign, not a good sign. Every disc you own is a disc your opponent can flip, so a bloated position gives them targets and options. I try to keep my footprint small and controlled for most of the game and only push for discs in the final handful of moves.
2. Fight for the corners
Corners are the most valuable squares on the board because a disc placed in a corner can never be flipped. There is no line that can bracket it, so it becomes a permanent anchor that flips discs along both edges and radiates safety around it. Almost every strong game is decided by who wins the corner battle. I plan several moves ahead specifically to set up a corner for myself or to deny one to my opponent.
| Square type | Value | Why |
|---|---|---|
| Corner | Highest | Can never be flipped, anchors two edges |
| Edge | Good, with care | Hard to flip, but can open a corner if misplayed |
| Centre | Neutral early | Fine to occupy while you build position |
| Next to an empty corner | Dangerous | Often hands your opponent the corner |
3. Starve their mobility
Mobility means the number of legal moves you have available. The player with more good moves controls the game, and the player forced into bad moves loses. This is why holding fewer discs is often stronger: a small, tidy position keeps my options open while pushing my opponent toward moves they do not want to make. When I can reduce my opponent to a single legal move, and that move is a bad one, I have effectively taken control of the whole board.
4. Take edges carefully
Edge squares are valuable because they are difficult to flip, having no discs on their outer side. But they come with a trap. Playing carelessly along an edge can create the exact setup that lets your opponent slide into the corner. I treat edges as useful territory but never grab them on reflex. Before I take an edge square, I check whether it opens a path to a corner for my opponent, and if it does, I leave it alone.
5. Turn the tables in the endgame
The last ten or so moves are where the disc count finally matters, and this is when all the restraint pays off. If I have anchored a corner or two and kept my opponent short on good moves, the endgame is where I cash that advantage in, flipping large groups as the board fills. The key is to have set this up in advance. You cannot win the endgame from scratch in the endgame; you win it by controlling corners and mobility long before it arrives. Keep the corners, keep your moves flexible, and let the final flips break your way.
6. Beware the X-squares
The most costly mistake I see beginners make is playing on the squares diagonally next to an empty corner, often called the X-squares. Placing a disc there almost always gives your opponent a clean path to take the corner on their next move, and once they own that corner you cannot take it back. I treat those four diagonal squares as poison until the neighbouring corner is already settled. The same caution applies to the squares directly beside an empty corner along the edges. Learning to leave these squares alone, even when a tempting flip is on offer there, is one of the fastest ways to stop handing free corners to a stronger opponent. If a move only works by playing an X-square, I look for almost any other option first.
If you want the wider background on where this puzzle comes from, the Reversi article on Wikipedia is a worthwhile read.
FAQ
Is Reversi the same as Othello?
They are almost identical. Othello is a trademarked version with a fixed starting position and standard rules, while Reversi is the older, more general name. The strategy here applies to both.
Which corner should I aim for?
Any corner is equally valuable. The key is to take corners while denying them to your opponent, rather than favouring one over another.
Why am I losing when I have more discs?
Because the disc count in the midgame means almost nothing. A large lead early often signals that you have taken too many risky squares and given your opponent safe replies. Aim for position, not numbers.
What is the worst move in Reversi?
Playing an X-square, the diagonal next to an empty corner, is usually the worst, because it hands your opponent the corner. Avoid those squares until the neighbouring corner is resolved.