How to Play Lattice

For fans of classic Checkers and Draughts, Lattice is free online and plays in your browser with no download and no account. It is really three board games behind one start screen — Checkers, Reversi and Gomoku — each played solo against a minimax AI. Pick a game, pick a difficulty (Novice, Strategist or Grandmaster) and press PLAY. Difficulty sets how many plies ahead the AI searches; Novice also adds random noise to its scoring, so it will blunder on its own.

Checkers is standard 8x8 American draughts, played on the dark squares of a board set inside a glowing fractal backdrop of recursive diagonal lines. Your twelve teal men fill the bottom three rows; the AI's twelve magenta men mirror them across the top. A man slides one square diagonally forward. If an adjacent enemy piece has an empty square behind it, you jump over it to capture — and captures are mandatory: whenever a jump exists anywhere on the board, the pieces that can start one are outlined and nothing else will move. Tap a piece, then tap a ringed square. Where a jump chain branches, each ending is offered as its own destination, and the chain you choose then plays out one hop at a time. Reaching the far back rank crowns a king, which moves and captures diagonally in any direction — but crowning also ends the chain, so a jump that promotes stops there even if more captures were available. You win by removing every enemy piece, or by leaving the AI with no legal move; forty moves with no capture and no promotion is scored as a draw.

Reversi is Othello on the same 8x8 grid. You play teal and move first from the standard four-disc opening. A placement is legal only if it traps at least one unbroken line of magenta discs between the disc you put down and another of your own, and every disc in every trapped line flips to teal; pulsing dots mark the squares that are legal right now. If you have no legal placement your turn is skipped, and when neither side can move the larger army wins. Gomoku is played on a 15x15 grid of intersections. You place the first stone and the AI answers, and the first to line up exactly five in a row — across, down or diagonally — wins. Six or more in a row is an overline and does not count, so a line pushed past five stops being a win.

Scoring is per mode: Checkers pays 100 for every piece you still hold, 50 per king crowned and 25 per capture; Reversi pays 10 per disc; Gomoku pays a speed bonus that starts at 300 and falls by 2 for every move played. All three add 500 for the win. Three stars take a dominant result — six pieces left in Checkers, forty discs in Reversi, or a Gomoku win inside fifteen total moves.

Strategy Tips

• Take the centre in Checkers. The AI's own evaluation pays a bonus for the middle of the board and two points for every legal move a side has, so centre pieces score twice over — they command more diagonals and they keep your mobility up. Edge pieces can only attack in one direction; treat them as a wall, not a spearhead.
• Advance in supporting pairs, and trade when you are ahead. A single pushed piece is a free capture. Move men forward so that any jump the AI takes lands it where you can jump straight back. Once you are a piece up, every even exchange brings a forced win closer; when you are behind, keep pieces on the board and look for a fork instead.
• Race for a king — and know where the chain stops. The AI values a king at nearly twice a man, and one king can retreat, re-engage and chain jumps in any direction, so sacrificing a man to run a piece home is often worth it. Just remember that a jump which crowns ends there, so plan the arrival for a square you are happy to stop on.
• Use the forced-capture rule as a weapon. Captures are mandatory for the AI too. Offering a jump takes the choice away from it, which is the one reliable way to steer a search that is otherwise reading two, four or six plies ahead. On Novice, random noise in its scoring means it will sometimes pass up the best line without your help.
• Own the corners in Reversi. A corner disc can never be flipped, and the AI scores corners highest and the diagonal squares beside them worst — playing one of those while the corner is still empty usually hands it over. Holding fewer discs in the middle game is fine; the count only decides anything once the board fills.
• Make two threats at once in Gomoku. The AI takes an immediate five and blocks yours before it considers anything else, so a single open four is always answered. Wins come from one stone that creates two separate fours — and from not overshooting, because six in a row scores nothing.

What Makes Lattice Different

Most free browser checkers sites hand you one board and one scripted opponent. Lattice gives each of its three games a real adversary instead: a minimax search with alpha-beta pruning and a mode-specific evaluation, where the difficulty you choose sets how deep it searches and how much random noise it allows into its own scoring. Scores, stars and victory streaks are tracked separately for every mode and every tier, so a Grandmaster Reversi run never has to compete with a Novice Checkers clear. Nothing is held back: every mode and every difficulty is open from the first click, with no sign-up and no download.

A Short History of Checkers

Checkers is one of the oldest board games humans still play. An ancestor called Alquerque was played in Egypt as early as 3000 BCE; the modern diagonal-movement version emerged in 12th-century southern France, where players adapted Alquerque pieces onto a chessboard. For most of the 20th century, world champion Marion Tinsley was considered unbeatable. Between 1989 and 1994, a program developed at the University of Alberta became the first computer to win a human-vs-machine world championship in any game. In 2007 the same research group announced that checkers had been weakly solved — under perfect play by both sides, the game is a draw.