I recently built a four-way chessboard! If you are interested, this is how I built mine:
1. I bought 3 incredibly cheap chessboards (the junky cardboard kind) from target.
2. I took one, and layed it out as the center.
Then, I cut 3 by 8 square areas from my two other boards and put them next to the full board.
3. Then I taped the boards together and now I have a much sloppier looking version of the board above.
4. Lastly, I had to have pieces. I used one set of black and white pieces for two players, and used red tape on the another set for the other two players.
Ta-daa! It's a four-way chessboard!
I've already had a chance to play a game on it. There are lots of really interesting game variants that can be played. One is where you are on a team with the person opposite of you, and you can give up your king, and don't have to move it out of check, so long as your teammate still has their king. The first team to lose both kings loses.
Have any of you tried four-way chess? What rules did you use?
