Game Rules

Time Controls

Head-to-head tables offer clocks of 3, 5, 10, 20 or 30 minutes per player, with no increment. Scheduled tournaments set their own clock, shown on the tournament page.

Time is enforced server-side with millisecond precision. When your clock reaches zero, you lose.

Standard Rules

Standard chess rules apply, with the draw and clock rules set out below:

• Movement: Each piece moves according to standard rules. Pawns move forward, capture diagonally. Knights jump in an L-shape. Bishops move diagonally, rooks along ranks and files, and the queen combines both.
• Castling: Both kingside (O-O) and queenside (O-O-O) castling are supported, provided neither the king nor rook has moved, no pieces are between them, and the king does not pass through or land on a square under attack.
• En Passant: If a pawn advances two squares from its starting position and lands beside an enemy pawn, the enemy pawn may capture it as if it had only advanced one square. This must be done immediately on the next move.
• Pawn Promotion: When a pawn reaches the far end of the board (the 8th rank for White, the 1st for Black), it must be promoted to a queen, rook, bishop, or knight.

Win Conditions

• Checkmate: The opponent's king is in check and cannot escape. This is the standard win.
• Timeout: Your opponent's clock runs out. You win.
• Resignation: Your opponent resigns the game.
• Tiebreaker: In contest games, draws are resolved by tiebreaker (see Draw Resolution below).

Draw Resolution

A game ends in a drawn position on stalemate, insufficient material, or the seventy-five-move rule. These are automatic. There is no draw offer and no draw claim: repetition does not end a game here, so play continues until one of the three conditions above is reached.

Since all contests on SkillClassics have entry fees with on-chain settlement,every game must produce a winner. When a drawn position is reached, the tiebreaker determines the winner:

1. Material: The player with more material value wins.
2. Move Count: If material is equal, the player with fewer moves played wins. White moves first, so this favours Black when White made the last move.
3. Time Remaining: If moves are equal, the player with more time on their clock wins.
4. White (Host): If all else is equal, White (the game creator) wins.

Material leads deliberately. Settling a drawn position on the clock would reward speed rather than play, and would hand the decision to whichever player most needed the draw — so the tiebreak is decided on the board first.

Platform-Specific Rules

• Move Validation: Every move is validated server-side against the full rules of chess. Invalid moves are rejected instantly.
• Disconnection: Your clock keeps running while you are away. If you stay disconnected for 60 seconds after play has begun, you forfeit the game; reconnecting sooner cancels the forfeit.
• Anti-Cheat: The platform runs automated integrity checks to identify potential cheating. See our Fair Play Policy for details.

Overview

Two players compete with a standard 52-card deck over a best-of-5 match — the first to win 3 hands takes the match. The table creator picks the variant, which changes how you may end a hand (shown in the lobby before you join).

Variants

• Standard: Knock with 10 deadwood points or fewer, or go Gin.
• Straight Gin: No knocking — you must go Gin (0 deadwood) to end a hand.
• Oklahoma: The face-up upcard sets the maximum deadwood you may knock with this hand (e.g. a 6 means knock at ≤6). An Ace upcard means you must go Gin. The limit is re-read from the upcard each hand.

Hand Setup

• Hand Size: Each player is dealt 10 cards.
• Stock Pile: The remaining cards form the draw pile (face-down).
• Discard Pile: One card is turned face-up to start the discard pile.

Card Values

Melds

A meld is a valid combination of cards. Two types exist:

• Sets: 3 or 4 cards of the same rank in different suits (e.g., 7♥ 7♦ 7♣).
• Runs: 3 or more consecutive cards of the same suit (e.g., 5♠ 6♠ 7♠ 8♠).

Cards not part of any meld are deadwood. The goal is to minimize your deadwood points.

Turn Sequence

1. Draw: Draw one card from either the stock pile or the top of the discard pile. If you draw from the discard pile, you cannot immediately discard that same card.
2. Discard: Place one card face-up on the discard pile (returning your hand to 10 cards).
3. End Hand: Optionally knock, declare gin, or declare big gin (see below).

Ending a Hand

• Knock (≤10 deadwood in Standard): If your unmelded cards are at or under the knock limit, you may knock to end the hand; deadwood is then offset against the defender's lay-offs onto your melds. The limit is 10 in Standard, set by the upcard in Oklahoma, and knocking is disabled entirely in Straight Gin.
• Gin (0 deadwood): If all 10 cards form valid melds, declare gin. Your opponent cannot lay off cards. You score the opponent's deadwood plus a 25-point bonus.
• Big Gin (11 cards melded): If all 11 cards (before discarding) form valid melds, declare big gin. You score the opponent's deadwood plus a 31-point bonus.
• Stock Depleted: If the stock reaches 2 or fewer cards without a knock, the hand is void and a new hand is dealt. It does not count toward the 3 hand wins.

Scoring

• Normal Knock: Knocker scores the difference between the defender's deadwood and the knocker's deadwood.
• Undercut: If the defender's deadwood is equal to or less than the knocker's, the defender wins the hand and scores the difference plus a 25-point undercut bonus.
• Gin Bonus: Opponent's deadwood + 25 points.
• Big Gin Bonus: Opponent's deadwood + 31 points.

Best-of-5 Match Format

The first player to win 3 hands wins the match and receives the payout from the smart contract escrow. A void hand is dealt again. Hand wins (not cumulative points) determine the match winner.

Fair Shuffling

Card shuffling uses the same cryptographic commitment scheme as backgammon dice:

• The shuffle is committed before the game starts.
• The commitment is fixed before any cards are dealt.
• The committed shuffle is recorded with the match result.

Platform-Specific Rules

• Hidden Information: You can only see your own hand. The server enforces information boundaries — opponent cards are never sent to your client until revealed.
• Real-Time Meld Display: Valid melds in your hand are highlighted automatically as you play.
• Disconnection: Your clock keeps running while you are away. If you stay disconnected for 60 seconds after play has begun, you forfeit the game; reconnecting sooner cancels the forfeit.

Overview

Go (also known as Baduk or Weiqi) is the oldest strategy board game still played competitively. Two players place black and white stones on a grid, aiming to control the most territory. There is no limit on the number of stones — you place one stone per turn and the board fills up until both players pass.

The table creator chooses the board size (9×9, 13×13, or 19×19), the scoring rules (Chinese or Japanese), and an optional handicap. These are shown in the lobby before you join.

Table Options

• Board Size: 9×9 (quick), 13×13 (intermediate), or 19×19 (standard).
• Handicap (none, or 2–9 stones): In a handicapped game, Black's handicap stones are pre-placed on the star points and White moves first. Use it to balance players of different strength.
• Scoring: Chinese (area) or Japanese (territory + prisoners) — see Scoring below.
• Komi: Compensation for White. Defaults to 5.5 on 9×9 and 7.5 on 13×13/19×19; handicap games use 0.5 (the handicap stones are the compensation).

Board Sizes

Basic Rules

• Turns: In an even game Black plays first; in a handicap game Black's stones are pre-placed and White plays first. Players then alternate placing one stone per turn on any empty intersection.
• Liberties: Each stone has liberties — the empty points directly adjacent (up, down, left, right). A group of connected same-color stones shares liberties.
• Capture: When a stone or group has zero liberties (completely surrounded), it is captured and removed from the board.
• Suicide Rule: You cannot place a stone that would leave your own group with zero liberties, unless doing so captures opponent stones.

Ko Rule

SkillClassics uses simple ko: you cannot make a move that recreates the exact previous board position. This prevents infinite capture loops. The ko point is indicated on the board during play.

Passing & Game End

• Pass: A player may pass their turn at any time instead of placing a stone.
• Game End: When both players pass in a row, the game goes to a count. Both players press Accept result to confirm it, or either can press Resume play to keep playing; if neither responds within two minutes the count stands. Stones left on the board are counted as alive, so capture dead stones before you accept.

Scoring

The table creator selects one of two scoring systems. White always receives komi, and empty regions bordered by both colors are neutral (score for neither).

• Chinese (area): Your score = your stones on the board + the empty points your stones surround. White adds komi.
• Japanese (territory): Your score = the empty points you surround + the prisoners you captured. White adds komi.
• Komi: Compensation for Black's first-move advantage — 5.5 on 9×9, 7.5 on larger boards, or 0.5 in handicap games. The half-point ensures no ties.

Win Conditions

• Score: When the count is confirmed, the player with the higher score wins.
• Resignation: A player may resign at any time, conceding the match.
• Timeout: If a player's clock reaches zero, they lose.

Platform-Specific Rules

• No RNG: Go has no random elements inside the game — every game outcome is determined by player decisions alone.
• SVG Board: The board renders as an SVG with the gold/dark SkillClassics theme. Stone placement is click-based.
• Ko Indicator: The ko point is visually marked on the board to prevent illegal moves.
• Score Panel: Capture counts and komi are shown alongside the board; the final scores appear when the game ends.
• Disconnection: Your clock keeps running while you are away. If you stay disconnected for 60 seconds after play has begun, you forfeit the game; reconnecting sooner cancels the forfeit.

Basic Movement

Backgammon is played on a board with 24 points (triangles). In the standard game each player has 15 checkers (variants differ — see Table Options & Variants below).

• Dice Rolls: Two dice are rolled each turn. Each die represents a separate move. You may move one checker for each die, or play both dice with the same checker one after the other, as long as it can land on the point reached by the first die (either die may go first).
• Direction: Players move in opposite directions around the board. White moves from point 1 to point 24 and Black from point 24 to point 1. White's home board is points 19-24; Black's is points 1-6.
• Blocked Points: You cannot land on a point occupied by two or more of your opponent's checkers.
• Doubles: Rolling doubles gives you four moves instead of two.
• Forced Moves: If you can make a legal move, you must. If only one die can be played, you must play the higher one if possible.

Table Options & Variants

The table creator picks the variant, which is shown in the lobby before you join. Tables created in the lobby do not use the doubling cube.

• Standard: The classic opening position — 15 checkers per side.
• Nackgammon: Like standard, but each side starts with four back checkers, two on its 24-point and two on its 23-point, and one fewer checker on its midpoint and its 6-point (15 checkers per side). A slower, more positional opening.
• Hypergammon: Each side has just 3 checkers, all in the opponent's home board. A fast, tactical race — you win by bearing off all 3.

Hitting & the Bar

• Hitting: Landing on a point occupied by a single opponent checker ("blot") sends it to the bar.
• Re-entering: A checker on the bar must re-enter in the opponent's home board before any other moves can be made. The die roll must match an open point in the opponent's home board (points 1-6 for White, points 19-24 for Black).
• Stuck on Bar: If no points are available for re-entry, you lose your entire turn.

Bearing Off

• When: You can begin bearing off once all of your checkers are in your home board (points 19-24 for White, points 1-6 for Black).
• How: Roll a die and remove a checker from the corresponding point. If no checker is on that point, you must move a checker within your home board by that number. If you have no checkers on any higher point, you bear off from your highest occupied point instead.
• Winning: The first player to bear off all of their checkers wins — that's 15 in Standard and Nackgammon, or 3 in Hypergammon.

Win Conditions

• Bear Off: The first player to bear off all of their checkers wins (15 in Standard/Nackgammon, 3 in Hypergammon).
• Timeout: Your opponent's clock runs out. You win.
• Resignation: Your opponent resigns the game.
• Double Drop: Your opponent declines a double. You win the game. (Only on the scheduled events that use the doubling cube.)

Time Controls

Each player has a chess-style clock that ticks during their turn:

• Your Turn: Your clock counts down while you decide your move.
• Opponent's Turn: Your clock pauses; the opponent's clock ticks.
• Timeout: When your clock reaches zero, you lose immediately.
• Disconnection: Your clock keeps running while you are away. If you stay disconnected for 60 seconds after play has begun, you forfeit the game; reconnecting sooner cancels the forfeit.

Doubling Cube

The doubling cube adds a strategic layer to competitive backgammon. It is used only on selected scheduled events; tables created in the lobby do not use it. Where it is used:

• Initial Value: The cube starts at 1 (center of the board, available to both players).
• Doubling: Before rolling, a player may propose to double the cube value. The opponent can accept (take) or decline (drop).
• Dropping: If declined, the game ends immediately and the player who declined loses it.
• Taking: If accepted, the cube value doubles and passes to the accepting player. Only the cube holder can propose the next double. The cube value does not change the prize.

Scoring

The first player to bear off all their checkers wins the game and the prize. Gammons and backgammons are not scored separately, and the cube value does not change the prize.

Fair Dice

All dice rolls on SkillClassics use a cryptographic commitment scheme:

• Each roll is committed before the game starts.
• The commitment is fixed before any dice are rolled.
• The committed rolls are recorded with the match result.