Checkers

Checkers is the classic 8x8 diagonal board game. You play against an AI at three difficulty levels: Easy, Medium, and Hard. You play red pieces moving up the board. The AI controls blue pieces moving downward. Pieces move one square diagonally forward on dark squares. When you can jump an opponent's piece, you must. Jumps are mandatory here. Multi-jumps are required too. If another capture is available after you land from a jump, you must keep jumping with that same piece.

Get any piece to the far rank and it becomes a King, marked with a crown. Kings can move and jump diagonally in both directions. They're much stronger than regular pieces. The AI values them at 150 internal points vs. 100 for regular pieces. A 40-move draw rule applies. If 80 half-moves pass without a capture or promotion, the game is a draw. That stops indefinite stalling.

Difficulty controls the AI's minimax search depth. Easy searches 2 moves ahead, Medium 4, and Hard 6. You can switch difficulty between games using the HUD. Wins are tracked on the leaderboard.

Checkers, known as draughts outside North America, is one of the oldest strategy games still played competitively. Its roots trace to Alquerque, a game played in ancient Egypt and documented in medieval Spain in Alfonso X's Book of Games around 1283. The modern form, with diagonal movement and mandatory jumps on a 64-square board, emerged in 12th-century France and spread across Europe. English settlers brought it to North America as checkers.

The mandatory-jump rule that defines most modern play was standardized in the 18th century. International draughts uses a 10x10 board with 20 pieces per side. English draughts, and this version, uses the 8x8 board with 12 pieces per side. Checkers gained mathematical fame in 2007 when researchers at the University of Alberta announced that their program Chinook had solved the game completely. With perfect play by both sides, checkers is always a draw. The minimax algorithm used in this version is the same foundational approach that powered Chinook's early versions, though the search depth here tops out at 6 ply on Hard.