Question 1

Why can't I move that piece?

Accepted Answer

Because the move would leave your own king attacked, which the rules never allow. A piece shielding your king from an attack (a pinned piece) can only move along the line of that attack, if at all, and when you're in check only moves that get you out of it are legal. The board only highlights legal moves.

Question 2

How does castling work?

Accepted Answer

Pick your king and move it two squares toward a rook; the rook jumps over to the other side of the king by itself. You can castle only if neither the king nor that rook has moved this game, the squares between them are empty, your king is not in check, and it doesn't pass through or land on a square your opponent attacks.

Question 3

What is en passant?

Accepted Answer

When your opponent moves a pawn two squares forward from its starting square and it lands right beside one of your pawns, you can capture it as if it had moved only one square, by moving diagonally onto the square it skipped. You can only do it on the very next move; after that the chance is gone.

Question 4

Can I promote to something other than a queen?

Accepted Answer

Yes. When your pawn reaches the far side you choose a queen, rook, bishop or knight. A knight is sometimes the better choice, for example when it gives check or checkmate where a queen would not, or when a queen would stalemate your opponent.

Question 5

What's the difference between checkmate and stalemate?

Accepted Answer

Checkmate is when the king is in check and there is no legal way out: the player who delivered it wins. Stalemate is when the player to move is not in check but has no legal move at all: the game is a draw.

Question 6

When is a game drawn?

Accepted Answer

By stalemate; when the same position (same pieces, same player to move, same castling and en passant options) comes up three times; after fifty moves by each player with no capture and no pawn move; when neither side has enough pieces left to checkmate (for example king against king, or king and bishop or knight against king); or when both players agree.

Question 7

How good is the bot?

Accepted Answer

Easy moves mostly at random, but it takes a checkmate in one when it sees one, never allows one back when it has another move, and won't simply give away the piece it moves. Medium looks three moves ahead (its own and yours, in turn), plays out any exchange, and counts material. Hard thinks for about a second a move, usually looks four to seven moves ahead, and knows where pieces stand best. It's a real challenge for most casual players, but it can be beaten.

Question 8

Does the bot accept draws?

Accepted Answer

When it thinks it is behind, yes. When it thinks it is level or ahead, Medium and Hard decline. Easy is more easily persuaded.

Question 9

How do I play with a friend?

Accepted Answer

Choose Online room, create a room and send the five-character code or the link. No account is needed. Each of you picks your pieces, and the host starts once both players are in. The host plays White in the first game and the colors swap every game after. Rooms are deleted 24 hours after the last activity.

Question 10

What happens if someone leaves?

Accepted Answer

Leaving a game in progress ends it, and the player who stayed wins. A player whose connection drops shows as away and has five minutes to come back before that happens. If the host leaves, the other player becomes the host.

Question 11

Is there a clock?

Accepted Answer

No. Games are untimed, so take as long as you like over a move (online, as long as you stay on the page).

Question 12

Can we play on one device?

Accepted Answer

Yes. Local 2-player uses the same board and rules: make your move, then pass the device.

Question 13

What if I can't tell the two colors apart?

Accepted Answer

You don't need to. Every piece carries its side's mark in the corner (a dot, square, triangle, diamond, star, plus, bar or ring), and no two sides can pick the same pieces, so the mark alone tells you whose is whose.

Question 14

Is my record saved?

Accepted Answer

Your wins, losses and draws against each bot and in online games are counted in your browser's localStorage, along with how local games on that device went. They stay on your device. If you're logged in to a Detour account, your bot and online records are saved to your account too, and follow you to any device you log in on.