2 colour game in a 8x8 chessboard, B can always prevent A from winning
Source: Dutch NMO 2006 p5
September 21, 2019
winning strategycombinatoricsChessboardColoring
Problem Statement
Player and player play the next game on an by square chessboard.
They in turn color a field that is not yet colored. One player uses red and the other blue. Player starts. The winner is the first person to color the four squares of a square of by squares with his color somewhere on the board.
Prove that player can always prevent player from winning.