(These rules are the same regardless of which site you play atomic on)
All of the pieces move in exactly the same way as in normal chess.
During captures, in addition to the piece being taken and the piece that
is capturing, all pieces (but NOT pawns) within a one square radius of the
capture are also destroyed (for captures en passant, ground-zero of the
explosion is the square on the sixth rank which the capturing pawn lands).
Therefore pawns are only destroyed when they either take or are taken, while
all other pieces can ALSO be destroyed if within a one square radius of an
Moves that result in the explosion of your own king are illegal.
As a result of the previous rule kings can move together, a useful
defensive idea in many endgames.
Regardless of whether the check rule is being used, see The Check Rule,
any move which results in the enemy king being destroyed is legal. Therefore
any attacks on your own king can be ignored in this case.
The Check Rule:
(This rule can vary between different sites so it is important to check the
specific rules of where you are playing to make sure you are clear on it).
When there ISNT check (such as on the ICC - see Where to Play) the game
is won by the explosion of the enemy king, by capturing a piece on an
adjacent square or taking it directly.
When there IS check (such as on FICS or USCL - also see Where to Play) the
game can be won either by the explosion of the enemy king, ONLY possible by
capturing a piece on an adjacent square, or by checkmate.
The main differences between these rules are as follows:
The NON-check rule allows castling through check, often escaping from
otherwise deadly attacks, for example look at the position with white to
Here white can play
1.Re1(+). Now if the check rule IS being enforced then black is lost as
either 1...Kf8 or 1...Kd8 are answered by 2.Re8#, but if the check rule
ISNT being enforced then 1...0-0 is perfectly legal and any result is a
long way off
The main differences can be seen in the endgame. This is because of the
stalemate factor introduced when there IS check. When there ISNT check
stalemate, although possible, is extremely rare, from watching and playing
thousands of serious games I have never seen it. This is because in
positions that would normally be considered stalemate the king is obliged to
walk into check when it can be taken.
For example see the following basic endgame with white to move:
When the check rule ISNT being used 1.Rb2! wins, as either 1...Ka2 or 1...Kb1 are forced when the
black king can be captured. When the check rule is being used the position
is a complete draw, as white cannot force checkmate and there are no other
black pieces that could be captured when the king is on an adjacent square.
If 1.Rb2 the position is stalemate.
Copyright Tipau, 2005