In regular chess a queen is worth 9, rook 5, knight 3, etc. What is the equivalent heuristic in atomic chess?
The answer is, as expected, "it depends". To answer directly first, 2016 Atomic World Championship (AWC) winner, tipau, put the values as:
Pawn - 1 Knight - 1.5 Bishop - 1.5 Rook - 3 Queen - 6
As a somewhat strong player myself (two top-8 finishes in the AWC) who has extensively analysed atomic chess endgames, I would tend to agree.
The king has no value, but outside of stopping passed pawns in endgames and a few other special zugzwang compositions, it is almost useless.
Now to go deeper into the topic, do note that the piece values change during the game. General experience would give the following points to support the piece values:
- In an endgame, a minor piece is only slightly more than a pawn; if one side has N pawns + 1 minor piece while the other side has N+1 pawns, the side with the minor piece has a slight advantage (which may not be enough to win, depending on the position).
- In the middlegame, a minor piece is worth more than a pawn, but usually less than two pawns.
- A rook is generally worth more than a minor piece, especially when there are more open files for invasion. A minor piece + pawn can compensate for a rook in the endgame though, generally forcing the side with the rook to take a draw by perpetual check.
- Knights are generally better than bishops in the very early opening and endgame, but not in the middlegame.
- The bishop pair is much stronger than the knight pair or a knight + bishop.
- The queen's value is hard to pin down. Depending on the position, she can be worth less than B+N, or more than R+B+N+P, as seen in several common opening lines. It largely depends on the solidity of both sides' positions.
- Factors like piece activity, pawn structure, passed pawns and other non-material considerations also matter in any given position.
I would therefore recommend using the following rules of thumb instead of exact point values:
- B ~ N (depends)
- N/B slightly > P
- B+B > 2 minors
- R > N/B
- R ~ N/B + P
- R > P+P
- R < B+N
- Q somewhere between B+N and R+B+N+P