Goal

Yavalath is an abstract strategy game designed in 2007 by computer scientist Cameron Browne using his evolutionary program LUDI, and published by nestorgames. It is famous for its simple yet diabolical rule: Connect 4 to WIN, but connect 3 and you LOSE!

Components

Component	Visual	Description
White Stone		Player 1 piece.
Black Stone		Player 2 piece.
Red Stone		Player 3 piece (in 3-player games).
Hexagonal Board		Hexagonal grid of cells (Standard: Side 5, 61 cells).
Winning Line		Highlighted in green: 4 or more stones in an unbroken straight line (5 in Five-not-four).
Losing Line		Highlighted in red: exactly 3 stones in an unbroken straight line (4 in Five-not-four).

Setup

• The board starts empty.
• Turn order: White → Black (→ Red in 3-player games).
• Players take turns placing one stone of their colour on an unoccupied hexagonal cell .

Winning and Losing

After placing a stone, all unbroken straight lines along the 3 hexagonal axes through that stone are evaluated:

• WIN : If you complete a straight line of 4 or more stones of your colour (5 in Five-not-four), you immediately WIN!
• LOSE : If you complete a straight line of exactly 3 stones of your colour (4 in Five-not-four) without simultaneously completing 4, you immediately LOSE!
• Win takes precedence: If a single placement forms both a winning line and a losing line simultaneously, the WIN takes precedence and you win the game.
• Draw: If the board fills completely with no winning line, the game ends in a tie.

Pie Rule (Swap)

In 2-player games (when enabled), after Player 1 places their opening stone, Player 2 may either play a normal move or click Swap Color to take over Player 1's stone and colour.

Three-Player Rules

• Elimination: A player who forms a line of 3 stones is immediately eliminated.
• Obstacles: The eliminated player's stones remain on the board as permanent neutral blockers.
• Must-Block Rule: You must not allow the player whose turn comes next to win. If the next active player can win on their turn, you must place your stone on one of those winning cells to block them. This applies even if blocking eliminates you.
• The game ends when a player completes 4-in-a-row (wins), or when two players have been eliminated (the sole survivor wins).

Variants (table options)

• Board Size & Ruleset (Option 100):
  • Standard (Side 5) (default): 61 cells. Connect 4 to win, 3 to lose.
  • Five-not-four (Side 6): 91 cells. Connect 5 to win, 4 to lose.
  • Compact (Side 4): 37 cells. Connect 4 to win, 3 to lose.
• Pie Rule (Swap) (Option 101, 2 players only):
  • Enabled (default): Player 2 may swap colours on their opening turn.
  • Disabled: standard opening without swapping.

Controls on BGA

• Placing a stone: click any unoccupied cell to stage your piece.
• Confirming & Undoing: click blue Confirm move to finalize, or red Undo (or click another cell) to change your placement.
• Pie Rule: on Player 2's opening turn (if enabled), click Swap Color in the status bar to swap colours.
• Forced block: when required to block the next player, only the valid blocking cells are legal.
• Preferences: Colour-blind symbols on stones (Preference 100, default: Off): displays geometric symbols on stones.