Game Overview
Gridlock combines Sudoku's strategic number placement with Tic-Tac-Toe's territorial control. Two players compete to claim three 3×3 groups in a row on a 9×9 grid.
Rules
- Take turns placing numbers 1-9 in empty squares
- Follow Sudoku rules: Each number must be unique in its row, column, and 3×3 group
- Complete a group: The player who places the last number to fill a 3×3 group claims it
- Win the game: First player to claim three groups in a row (horizontal, vertical, or diagonal) wins
Dead Cell Penalty
If your move makes it impossible to complete a group without creating a dead cell (a square with no valid numbers):
- Your move is removed from the board
- The affected group is auto-completed for your opponent
- Your opponent claims that group
- You get to try again with a different move
Visual Indicators
- Blue highlight: Safe moves
- Red highlight: Dangerous moves that create dead cells
- Yellow ring: Cell with 2 valid numbers remaining
- Orange ring: Cell with 1 valid number remaining
- Show Hints: Toggle to see how many valid numbers each cell has
Strategy Tips
- Watch for moves that would force your opponent into a bad position
- Pay attention to cells with limited options
- Plan ahead to avoid creating dead cells
- Control key groups early to set up your winning line