Overview

Dao is a two-player abstract strategy game played on a 4x4 grid. It won the Mensa Select award in 2001. The game has a single movement rule and three ways to win. Players alternate turns sliding their pieces as far as possible in a chosen direction. The simplicity of the rules belies a surprisingly deep strategic game.

Components

• 1 game board (4x4 grid)
• 4 pieces per player (2 colors), 8 total

Setup

Players place their pieces in an X pattern across the board: each player’s 4 pieces are placed diagonally from corner to corner. One player occupies two opposite corners and the diagonal between them; the other player occupies the other two corners and their diagonal.

Turn Structure

Players alternate turns. On your turn, move one of your pieces.

Actions

Movement

• Choose one of your pieces and move it in any direction: horizontally, vertically, or diagonally.
• The piece must slide as far as possible along the chosen direction until it reaches either the edge of the board or is stopped by another piece (friendly or enemy).
• You cannot move a piece if it would not change position (already at the edge/blocked in the chosen direction).

Scoring / Victory Conditions

A player wins by achieving any one of these three formations:

Formation	Description
Four in a Row	Place all 4 of your pieces in a horizontal or vertical line. (Diagonal lines do NOT count.)
Four Corners	Occupy all 4 corner spaces of the board with your pieces.
2x2 Square	Form a 2x2 square of your pieces anywhere on the board.

Special Rules & Edge Cases

• Forced maximum movement: A piece must always slide as far as it can. You cannot stop partway.
• Diagonal four-in-a-row does not win: Only horizontal and vertical rows of 4 count.
• Blocking: A piece stops when it reaches the board edge or encounters any piece. There is no jumping or capturing.
• No captures: Pieces are never removed from the board.
• No passing: You must make a move on your turn if any legal move exists.

Player Reference

Movement: Slide 1 piece in any of 8 directions; must go as far as possible

Win Conditions (any one):

1. Horizontal or vertical 4-in-a-row
2. Occupy all 4 corners
3. Form a 2x2 square anywhere

Board: 4x4 grid, 4 pieces per player, no captures