Pepito

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Pepito, a Chess Engine Communication Protocol and UCI compliant open source chess engine written by Carlos del Cacho in C, first released in September 2000. The recent version comes with an own GUI written in C++ using wxWidgets and can create opening book databases from a pile of thousands of chess games, applying advanced data structures such as B-trees and skip lists. As bitboard engine, Pepito applies rotated bitboards with 1/2 MiB lookup tables, indexed by the full 8-bit line occupancy, to determine sliding piece attacks. Pepito played the CCT4, CCT5 and CCT6 tournaments.

=Screenshot= Pepito GUI

=Features=
 * NegaScout search algorithm
 * Extensions to avoid horizon effect (i.e. check, recapture, pawn push, ...)
 * Transposition tables, pawn hash tables and evaluation cache
 * AEL-pruning à la Heinz
 * Static exchange evaluator, used for move ordering and also to cull losing captures in the quiescence search
 * Lazy evaluation
 * Nalimov Tablebases
 * Pondering
 * Book learning

=Acknowledgments= Pepito wouldn't have come to life without the help from these guys, acknowledged by Carlos del Cacho in thanx.txt, shipped with the source files :
 * Bob Hyatt (Crafty)
 * Dušan Dobeš (Phalanx)
 * Daniel Homan (EXchess)
 * Adrien Regimbald (Faile)
 * Jon Dart (Arasan)
 * Andrew Tridgell & Jonathan Baxter (KnightCap)
 * Stuart Cracraft & Chua Kong Sian (GNU Chess 5)
 * John Stanback (GNU Chess 4)

... further ...
 * Eugene Nalimov for his Endgame Tablebases

... and
 * Jonathan Schaeffer
 * Alexander Reinefeld
 * Ernst A. Heinz
 * Aske Plaat

for their papers, and
 * Bruce Moreland
 * Dieter Bürßner
 * Brian Richardson
 * Tony Werten

and many others at CCC for their help...

=Selected Games= CCT4, round 2, Pepito - Yace [Event "CCT4"] [Site "Internet Chess Club"] [Date "2002.01.19"] [Round "2"] [White "Pepito"] [Black "Yace"] [Result "1/2-1/2"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Be3 e6 7.f3 b5 8.g4 h6 9.Qd2 Nbd7 10.O-O-O Bb7 11.h4 b4 12.Na4 Qa5 13.b3 Nc5 14.a3 Rc8 15.Qxb4 Qc7 16.Nxc5 dxc5 17.Qa4+ Nd7 18.Ne2 c4 19.b4 Bc6 20.Qxa6 Ra8 21.Qxc4 Rxa3 22.Bf4 Qb7 23.c3 Bb5 24.Qd4 Ra2 25.Kb1 Rxe2 26.Rh3 e5 27.Bxe5 Bc5 28.Qd5 Bc6 29.Qc4 Bb5 30.Qd5 Bc6 31.Qc4 Bb5 32.Qd5 1/2-1/2

=Clones= The program Siboney by Francisco Rivera published in 2002 was based on Pepito with a changed evaluation. In 2003, Deep<9> by pretended author Denis Grafen was proven a blatant clone of Pepito.

=Forum Posts=

2000

 * New winboard engine released! by Carlos del Cacho, CCC, September 18, 2000
 * Pepito 1.01 uploaded! Bugfix + adjustable hash size by Carlos del Cacho, CCC, September 20, 2000
 * About Pepito and Amyan by José Carlos, CCC, September 24, 2000 » Amyan
 * Pepito 1.03 available (Move now support & José C. bug fixed) by Carlos del Cacho, CCC, September 25, 2000
 * Pepito v1.10 available w source by Carlos del Cacho, CCC, December 22, 2000

2001

 * Pepito 1.40 MMX LCT2 test by Gabor Szots, Winboard Forum, October 02, 2001 » LCT II
 * Pepito 1.42 MMX build by Dann Corbit, Winboard Forum, October 04, 2001

2002

 * The New Pepito... by Dann Corbit, Winboard Forum, June 24, 2002
 * new Pepito version available for download by Carlos del Cacho, Winboard Forum, July 27, 2002
 * Config.dat for Pepito by Carlos Pesce, Winboard Forum, July 30, 2002
 * New format of Config.dat for Pepito (built from the readme!) by Günther Simon, Winboard Forum, July 30, 2002
 * Pepito 1.55 ( Read for fixes) by Nolan Denson, CCC, July 31, 2002
 * Siboney = a Pepito clone ?? by Brice Boissel, Winboard Forum, August 06, 2002
 * Pepito 1.54 and learning by Igor Korshunov, Winboard Forum, November 12, 2002

2003

 * Deep<9> Is a Clone based of Pepito? Really? by Volker Richey, CCC, March 13, 2003
 * Deep9, Pepito and Leo's Qualify by Matthias Gemuh, Winboard Forum, March 13, 2003

2004 ...

 * Pepito @ CCT6 After thoughts by Nolan Denson, CCC, February 01, 2004
 * Pepito problem by Tord Romstad, Winboard Forum, March 10, 2004
 * Pepito 1.59 Windows 64-bit build available by Jim Ablett, CCC, December 20, 2007

=External Links=

Chess Engine

 * Pepito Chess engine on Behance
 * Pepito... that other xboard chess engine hosted by Thomas Mayer
 * Index of /chess/engines/Norbert's collection/Pepito (Compilation) by Norbert Raimund Leisner, hosted by Kirill Kryukov
 * Pepito in CCRL 40/15

Misc

 * Pepito (disambiguation) from Wikipedia
 * Pepito (sandwich) from Wikipedia
 * Pepe (disambiguation) from Wikipedia
 * Pepito (comics) from Wikipedia

=References= Up one Level