Bruja

Hans Baldung - Witch and Dragon, 1515 ¹

Hans Baldung, Stehende Hexe mit Ungeheuer, 1515; Feder, weiß gehöht, auf braun grundiertem Papier, 295 × 207 mm, Wikimedia Commons ↩︎

Bruja,
a WinBoard compatible chess engine by Dan Honeycutt, written in C++ and first released in March 2004. In the program's readme file, Dan Honeycutt states that Bruja would never had come to be without the contributions of others, and credits Adrien Regimbald, Bruce Moreland, Robert Hyatt, Carlos del Cacho, and Ed Schröder with their respective programs and descriptions as source of inspiration ¹ . A stripped version of Bruja, called Simon, was published as open source engine ² .

Contents

Description

Bruja has a bitboard infrastructure, and uses rotated bitboards to determine sliding piece attacks. It performs strictly legal move generation.

Search

Bruja applies PVS with transposition table inside an iterative deepening fractional ply framework in conjunction with null move pruning, singular, recapture and passed pawn extensions.

Evaluation

Bruja's evaluation initializes attack tables as described in Evaluation in REBEL by Ed Schröder ³ , to do hanging piece and static exchange evaluation, and to apply progressive king safety evaluation. Further, Bruja has some pawn structure knowledge and applies piece-square tables ⁴ .

Etymology

Bruja is the Spanish word for Witch and can mean some worse things depending on context ⁵. The development of Bruja has started on Friday, October 31, 2003, during the Halloween storm when major flares erupted on the Sun with heavy influence on the Earth ⁶ and spectacular aurora with green phantom “northern lights” seen as far south as Texas, Georgia and Florida ⁷.