Checkers

The board, and how you win

The board is 8×8 and only the 32 dark squares are ever used, so every move and every capture happens on a diagonal. Each side starts with 12 pieces on the 3 dark rows nearest it. You are always drawn at the bottom of the screen: your pieces advance toward the top, the CPU’s advance toward you.

You win when the CPU has no piece left, or when it has no legal move on its turn. Being shut in is the same ending as being taken apart — the side that cannot move loses. At the end the screen shows how many pieces each side had left.

• A match is a draw after 50 turns in which nobody captured and no man moved. By then only kings are shuffling, the material has not changed and nothing has come closer to a crowning, so the position can only repeat.
• The rules are English draughts — the version most people mean by "Checkers". The international 10×10 game, with kings that slide the length of a diagonal and a duty to take the most pieces, is a different game and this is not it.
• Repeating the same position three times is not a draw here. One counter, turns since the last capture or man move, gives the same ending without carrying a history of positions around.
• There is no score and no clock. A result is a win, a loss or a draw plus the pieces left standing, and your playing time is kept for your statistics rather than shown on the board.
• Only a match that actually finished is recorded. Start a new one part-way through and it does not count as a loss — the record is there to be read, not to hold anything over you.

Moves, captures and kings

A man moves one square diagonally forward onto an empty dark square. A capture jumps an enemy piece standing diagonally next to it and lands on the empty square directly beyond; a man jumps forward only.

If any of your pieces can capture, a capture is the only thing you may play. Which capture you take is your own choice — nothing here forces you to take the most pieces. That single obligation is where the tactics come from: when your opponent has only one capture available, giving a piece away decides their next move for them.

• Chain jumps. If the piece that just landed can jump again, it must, and it must be that same piece. However many pieces it takes, the whole chain is one turn.
• Crowning. A man that reaches the far row becomes a king, marked by a ring inside the piece — shape rather than colour, so it reads the same for every player.
• Kings move and jump one square diagonally in any of the 4 directions. They do not fly down the diagonal; that belongs to the international game.
• A crowning ends the turn. If a man is crowned in the middle of a chain, the sequence stops right there, even when the new king could jump again.
• The obligation to capture binds the CPU at every difficulty, Easy included. It is a beginner, not a player with different rules.

Controls

Picking a piece up and putting it down are two separate taps. There is no dragging, and nothing on the board is pressable except the pieces that can move and the squares the piece you are holding may go to.

• Tap one of your pieces to pick it up. Its destinations show a dot; tap one to move there, or tap the piece again to put it back down.
• Tapping anything else does nothing and makes no sound. While a capture is on, the pieces that cannot jump are simply not pickable — the rule is enforced by what is offered, not by an error message.
• In the middle of a chain the piece stays picked up for you, so the second jump is a single tap.
• The piece that moved last carries a small mark, and the CPU plays a chain one jump at a time, so you never have to reconstruct what it did.
• Who moves first is chosen on the home screen: "You first" or "CPU first". It applies to the next match — a match already in progress keeps the side it started with.
• Leave mid-match and the position is kept, including an unfinished chain: you come back to the piece that still has to jump. Undo history is not saved, so a resumed match starts from that position.

Undo, and the help the board gives you

Undo is unlimited and free. It steps back to your own last decision, which means your move and the CPU’s reply come off the board together — a position where the CPU is to move is not a place where you decided anything.

Undo is not a re-roll. The CPU is deterministic: put the board back, play the same move again, and the same reply comes back. What Undo buys is the chance to read a line out and back up, not another draw from a hat.

• The pieces that can move are the only ones you can pick up, and their destinations are marked. That is true every turn, not only when a capture is on.
• The turn line under the board holds a fixed height so nothing jumps, and says one thing at a time: "Your turn", "A capture is on — only the pieces that can jump may move", "Jump again with the same piece", or that the CPU is thinking.
• This is the rules made visible, not advice. It shows you what is legal and never which legal move is better — when two captures are available, choosing between them is entirely yours.
• Undo pressed in the middle of a chain takes the whole sequence back to before it started. A forced second jump is not a place where you decided anything, so it is not a place to stop.
• There is no Hint. The whole position is visible and nothing is hidden, so a suggested move could only be the CPU playing your side as well as its own.
• Undo and the legal-move display are the entire help system. Both work from the first launch, and no game feature is ever behind an ad or a purchase.

Easy, Normal and Hard

There are 3 opponents and they differ in one thing: how far ahead the CPU looks. None of them gets extra pieces, extra turns or anything you cannot see, the obligation to capture binds all 3, and all 3 can be picked from the first launch — no strength is unlocked by playing or by paying. A move below means one side’s turn, so 3 moves ahead is the CPU’s move, your reply, and its move after that.

• The search runs on your device, and it starts only after you have moved. Nothing is thinking on your time.
• A chain of jumps is read as one move rather than several, so the search does not go shallow exactly where the position is sharpest. It also keeps reading past its depth limit while captures are still forced, so it never stops counting in the middle of an exchange.
• The search counts the 50-turn draw as a real ending. A CPU that did not know the game can end that way would read on past a draw it is one move from causing, and hand one away while it was ahead.
• The reply lands after a beat of about 450ms, and the search runs after that beat rather than inside it — so a slow reply arrives a little later than a quick one. Between the jumps of one chain the beat is a shorter 260ms, because that is one move still being made rather than an opponent thinking.
• The opponent is always the CPU. There is no online play, no second player on the same device, and no rating or ranking — your record against each difficulty stays on your device.
• There is no level list, no daily match and no streak. Every match starts from the same position, 12 pieces a side, and the only thing you choose is the opponent.

What Hard is weighing is a plain evaluation: a man is worth 100 and a king 165, with small credit for advancing, for keeping your own back row and for the edge columns. There is no opening book and no endgame database. It thinks well within its budget; it does not solve the game, and it is not meant to be unbeatable.

Tips

• Count the exchange before you move. Because your opponent must take, giving a piece away is a way to choose their reply — and if your recapture takes two of theirs, you came out a piece ahead by handing one over.
• When you are ahead in material, trade pieces. Every pair that leaves the board makes your extra piece a larger share of what is still on it.
• A piece in the outermost column cannot be jumped at all: a jump needs the square directly beyond, and beyond the edge there is none. It is also slow there, with only one forward diagonal to move on, so the edge is a place to park a piece rather than to attack from.
• Keep your own back row occupied for as long as you can. An enemy man crowns by reaching it, and pieces already standing there leave it nowhere to land.
• When you set a sacrifice up, look at where the forced chain ends. A chain that finishes on your own back row stops there, because crowning ends the turn — but it has just made the CPU a king, which is usually the worse half of that trade.
• Work out who gets the first king. It is the only piece that can move backwards, which makes it the one piece that attacks and defends at the same time, and in a close endgame that usually settles it.

Undo is the study tool in this game. Because the reply is the same every time, taking a move back and trying something else shows you what the other line actually does — that is reading, not re-rolling.

Questions people ask