Help & Game Guide
Royal Gambit is a browser-based chess game you can play instantly — no download or account required. Challenge a built-in AI opponent or sit back and watch two AIs compete on a beautiful, animated board.
Play online at linhtruong.com/game/chess. The game runs entirely in your browser and works on desktop, tablet, and mobile.
You play against the computer. Select Play vs AI in the header, then configure:
When playing as Black, the board flips automatically so your pieces appear at the bottom. Use Undo to take back moves — it removes your last move and the AI's response.
Watch two AI opponents play each other. Great for learning openings, studying strategy, or simply enjoying the show.
The board is view-only in this mode — you cannot move pieces manually. Undo is disabled; use New Game to restart.
| Control | Action |
|---|---|
| Click piece → click square | Select and move (Play vs AI only) |
| ↕ Flip | Rotate the board 180° (change perspective) |
| ↩ Undo | Take back move(s) — Play vs AI only |
| ♟ New Game | Reset the board and start over |
| 🔊 / 🔇 | Toggle sound on or off |
| Mode switcher (header) | Switch between Play vs AI and AI vs AI |
e4, Nf3, O-O).Royal Gambit includes procedural sound effects — no downloads required. Sounds play for moves, captures, castling, checks, checkmate, and UI actions.
| Control | Location |
|---|---|
| 🔊 / 🔇 button | Below the board — quick mute toggle |
| Sound effects toggle | Left panel → Sound |
| Volume slider | Left panel → Sound (0–100%) |
Browsers require a click or tap before playing audio. If you hear nothing at first, click anywhere on the page, then make a move.
When a pawn reaches the opposite end of the board, a popup lets you choose: Queen ♕, Rook ♖, Bishop ♗, or Knight ♘. Queen is the strongest choice in almost every situation.
Files (columns) are labeled a through h from left to right. Ranks (rows) are labeled 1 through 8. In the default view, White starts on ranks 1–2 at the bottom; Black on ranks 7–8 at the top.
The evaluation bar estimates who is winning based on material and piece placement. A score of +1.0 means White is roughly a pawn ahead; −2.0 means Black is about two pawns better. It updates after every move and is especially useful in AI vs AI mode.
Moves are recorded in algebraic notation:
| Symbol | Meaning | Example |
|---|---|---|
| (none) | Pawn move | e4 |
| N, B, R, Q, K | Knight, Bishop, Rook, Queen, King | Nf3 |
| x | Capture | Bxf7+ |
| + | Check | Qh5+ |
| # | Checkmate | Qh7# |
| O-O | Kingside castle | O-O |
| O-O-O | Queenside castle | O-O-O |
| =Q etc. | Promotion | e8=Q |
The AI uses a minimax search algorithm with alpha-beta pruning. Higher levels think more moves ahead.
| Level | Search Depth | Best For |
|---|---|---|
| Easy | 2 moves ahead | Beginners learning the rules |
| Medium | 3 moves ahead | Casual players (default) |
| Hard | 4 moves ahead | Intermediate players wanting a challenge |
| Expert | 5 moves ahead | Experienced players — AI may take a few seconds per move |
The AI evaluates positions based on piece values, board control, and check threats. It is strong for a browser engine but not comparable to dedicated chess software.
Chess is a two-player strategy game played on an 8×8 board. Each player starts with 16 pieces: one king, one queen, two rooks, two bishops, two knights, and eight pawns.
Objective: Put the opponent's king in checkmate — a position where the king is in check and has no legal escape. You do not capture the king; the game ends the moment checkmate is unavoidable.
White always moves first. Players alternate turns, moving one piece at a time (except castling, which moves king and rook together). You may not move into check or leave your own king in check.
| Piece | Symbol | Value |
|---|---|---|
| Pawn | ♙ ♟ | 1 |
| Knight | ♘ ♞ | 3 |
| Bishop | ♗ ♝ | 3 |
| Rook | ♖ ♜ | 5 |
| Queen | ♕ ♛ | 9 |
| King | ♔ ♚ | ∞ (priceless) |
Moves forward one square. On its first move, it may move two squares. Captures diagonally one square forward. Cannot move backward.
Moves in an L-shape: two squares in one direction, then one square perpendicular. The only piece that can jump over others.
Moves any number of squares diagonally. Each bishop stays on one color for the entire game.
Moves any number of squares horizontally or vertically. Especially powerful on open files and in the endgame.
Combines rook and bishop movement — any number of squares in any straight line (horizontal, vertical, or diagonal). The most powerful piece.
Moves one square in any direction. Must be protected at all costs. Can castle under specific conditions (see below).
A one-time move combining the king and a rook. The king moves two squares toward the rook; the rook jumps to the other side of the king.
Requirements — all must be true:
If an opponent's pawn moves two squares forward from its starting rank and lands beside your pawn, you may capture it as if it had only moved one square — but only on the very next turn.
Example: White pawn on e5, Black plays d7→d5. White can capture on d6 immediately. If White does not capture right away, the opportunity is lost.
When a pawn reaches the farthest rank (8th for White, 1st for Black), it must be promoted to a Queen, Rook, Bishop, or Knight. Nearly always choose Queen — Royal Gambit will prompt you to pick.
Royal Gambit does not currently detect threefold repetition or insufficient material draws. In those rare cases, you may agree to a draw by starting a new game.
No. Royal Gambit runs entirely in your browser with no sign-up, login, or personal data required.
Yes. The layout adapts to smaller screens. Tap a piece, then tap a highlighted square to move.
Castling requires that neither piece has moved, the squares between them are empty, the king isn't in check, and no square the king crosses is attacked. Bishops on f1/c1 commonly block castling at the start — develop them first.
En passant is only available the move immediately after the opponent's pawn jumps two squares. You must capture on that turn or the chance is gone.
Most browsers block audio until you interact with the page. Click anywhere on the board or press a button, then try again. Also check that sound is enabled in the left panel and the 🔊 button below the board isn't muted.
It shouldn't — you only control your chosen color (White or Black). If both sides move automatically, refresh the page and start a new game. Make sure Play vs AI is selected in the header, not AI vs AI.
Not currently. Refreshing the page starts a new game. Use the move history panel to review the current game.
Expert difficulty searches five moves ahead, which takes longer as the position opens up. Try Medium or Hard for faster responses.
Yes. Upload the game folder to your server and link to index.html, or embed it in an iframe. See the project README.md for deployment and iframe examples.
Put your knowledge to the test on the board.