An Atomic Chess Introduction

By Nick Long, Third Edition -- January 10, 2009

Part I. What is Atomic Chess?

Atomic Chess is a chess variant. The rules of chess are in effect for Atomic Chess and the opening position is the same as regular chess. However, Atomic Chess adds a few unique rules to make it a different game from chess. Those rules may appear straightforward and simple but they do produce a few quirky situations in the middle of a game. However, that is part of the appeal of Atomic Chess.

Here are the rules for Atomic Chess:

The rules of normal chess apply to Atomic Chess with the following extensions:

Whenever a piece is captured, an explosion occurs on the field around the capture. This explosion destroys the following pieces:
(a) The capturing piece.
(b) The captured piece.
(c) All other pieces EXCEPT pawns on the 9x9 grid around the captured piece's square.

Destroyed pieces are removed from the board.
An Atomic Chess game is won by causing the explosion of the opposing king. An atomic checkmate may occur when the King cannot prevent his own explosion with any other moves. Please note that this leaves open the possibility of having a regular chess checkmate occurring on the board, however this will not end the game. Only a direct explosion or unpreventable explosion (Atomic-Mate) will end an Atomic Chess game.
Moves causing your own king's explosion are NOT allowed.

Note that this rule will allow for the two kings to end up next to each other on the chess board. This will not end the game.

Part II. Understanding Captures in Atomic

Understanding how captures work in atomic is best demonstrated visually. So I'll provide a diagram and then demonstrate how various captures would affect the board:

FEN: 8/8/2pbn3/2RpP3/3NP3/8/8/8
Captures Aplenty! (Illegal Atomic-Chess position as well)

If we take a look at this position, we can see a variety of captures possible. Here's how some of them will affect the board:

FEN: 8/8/2pbn3/2R1P3/8/8/8/8	FEN: 8/8/2p5/4P3/8/8/8/8
After Black moves dxe4	After White moves exd5
FEN: 8/8/2p5/2RpP3/4P3/8/8/8	FEN: 8/8/2pb4/3pP3/4P3/8/8/8
After White moves Nxe6	After Black moves Nxd4
FEN: 8/8/2p5/2RpP3/4P3/8/8/8	FEN: 8/8/4n3/3pP3/3NP3/8/8/8
After Black moves Bxc5	After White moves Rxc6
FEN: 8/8/2p5/4P3/4P3/8/8/8	FEN: 8/8/2p1n3/2Rp4/4P3/8/8/8
After White moves Rxd5	After Black moves Bxe5

Part III. How an Atomic game ends

Now that you've learned how captures in Atomic Chess affect the board, it's time to learn how an atomic game ends. In chess, there are two ways in which a game can end apart from a repetition draw and draw by agreement by the players or various other results possible by extraneous rules -- checkmate and stalemate. Atomic chess has three ways: explosion, atomic-mate and stalemate. Explosion is very easy to understand, once you explode the other player's king, you automatically win the game. This is the most direct way of ending a game. Atomic-Mates is similar to checkmate in chess in that it forces an explosion the next move which cannot be prevented. The person delivering the atomic-mate wins. Lastly, stalemate in atomic is a difficult position to achieve but if somebody is stalemated, the game ends in a draw.

Explosion

FEN: rnbq3r/ppp3pp/4p3/3p4/8/8/PPPPPPPP/RNBQKB1R

Atomic-Mate

FEN: 5rk1/5p1p/5BpN/2b2N2/8/8/5P2/4K3	FEN: 5rk1/5p1p/5BpN/2b2N2/8/8/8/4K3
This is NOT Atomic-Mate. Black wins by Bxf2, exploding White.	This is Atomic-Mate. White wins.

Stalemate

FEN: 8/8/8/8/8/8/5QQ1/5kK1	FEN: 8/8/8/8/8/8/5QQ1/5kK1
White wins.	This is stalemate. Game is drawn. (Black cannot make a legal move)

[First Edition : 03 August 2002 -- Nick Long]
[Second Edition : 15 March 2005 -- Nick Long]
[Third Edition: 09 January 2009 -- Nick Long]
[Last Modified : 20 February 2009 -- Nick Long]
© 2009 Nick Long