Three4Chess.com
Printer Friendly Rules
Three Player Chess uses the same basic movement techniques as found in the traditional two player rendition. In a sense the only confusion arises when we look the the centre of the board - in particular the middle six ‘squares’ - and the ending.
Starting
The pieces are laid out the same way
as with two player chess. Normally it is important to remember that the queen
should start on its own color, with the three player variation this is less
important, however players should attempt to match the square colour and the
piece colour as closely as possible. In this game white starts and moves go
counter-clockwise.
The Center Squares
There are two basic rules which should always be considered when looking into
possible movements involving the center ‘squares’. The first is
that to continue on a diagonal line one must depart and arrive on ‘squares’ the
same colour. With this in mind the second rules follows that by moving forward,
straight, one square will the piece will be on a different colour.

In the following situation we pick up the game after which two moves have been played by each player - with white next to move. Moving the pawn forward will result it landing on the red square, labeled A. However, as in the traditional game of chess, pawns can (only) take diagonally. Therefore it may take the the black pawn, labeled B. In addition to this it could potentially take any piece located on the squares C and D. Further to this it may move forward to the square labelled E. These are the only moves it is permitted to make and, hopefully, show the difference between moving forward, squares A and E., compared to diagonally, squares B., C and D.

Now consider another situation. Black to move. We are not suggesting
that this is the best move, only it shows some of the potential for taking
advantage of the diagonal play available. We are going to concentrate on the
black queen. The arrows represent all possible moves; you will notice that
at the center it has two options, to attack either the blue or white rooks.
As long you always remember the diagonal=same colour formula no issues should
arise.
(The observant of you will notice that blue is in check by black, and because
turns go anti-clockwise, blue would have been forced to move its king before
the following black turn which has been used in the example..!)
The Ending
There are two possible ending situations that can played. The first, a last
man standing scenario - were the first check-mated player is eliminated (their
pieces can be removed, or kept as a ‘forest’ - but this makes
things much harder..!) and the game continuing between two players or a shortened
game, at which the first player checkmated loses along with one other - the
winner being the player who's pieces actually check mate. There are situations
when both players combined pieces check mate someone, if this happens the
winning player is whoever first checked the checkmated party. In the above
example, suppose that blue was in a situation where it was check-mated by
black queen. It would miss its turn. White would then have the opportunity
to counter the black checkmate - after all it would lose with blue. If this
is not possible then the checkmate is confirmed, and the game ended - or
blue eliminated - depending on the ending variation being played.
We hope that you find this guide useful. Three Player Chess is a young game and we are sure that as you play more you will think of your own variations.
If you have any questions, please send a message via the website.