# power

The*power*of a piece is its material value

Piece type | power |
---|---|

pawn | 1 |

knight | 3 |

bishop | 3 |

rook | 5 |

queen | 9 |

king | 0 |

empty square | 0 |

The power of a set of squares in a position is the sum of the power of all the pieces on squares in that set in the position.

## power filter

The`power`

filter consists of the word `power`

followed by a set filter:
power A

A power filter has a numeric value equal to the power of the pieces on the squares denoted by its set filter.

Thus, `power A>= 15`

matches positions where the power (material value) of the White pieces is at least 15.

The diagram below shows the earliest first prize win study with an initial total power of 7:

(found from CQL file: power7firstprize.cql)

The `power`

filter can also be used to find material imbalances, as in the study below where
black wins despite having a large material advantage, and white having only a single pawn:

(found from CQL file: powerA1alarge.cql)

# Examples

The`power`

filter is used in massivestalemate.cql, pinstalemate.cql, and powerdifference-stalemate.cql.