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Defenchess,
an UCI compliant open source chess engine by Can Cetin and Dogac Eldenk, written in C++, licensed under the GPL v3.0. Defenchess evolved from the author's former engine SCTR ¹, and had its tournament debut at TCEC Season 11 in 2018, where it won the Fourth Division ².

Features

³

Board Representation

• 8x8 Board
• Bitboard Board-Definition
• Plain Magic Bitboards

Search

• Lazy SMP
• Iterative Deepening
• Alpha-Beta
• Principal Variation Search
• Transposition Table
• Selectivity
  • Null Move Pruning
  • ProbCut
  • SEE Pruning
  • Late Move Reductions
  • Futility Pruning
  • Razoring
  • Check Extensions if SEE >= 0
  • Restricted Singular Extensions
  • Quiescence Search
• Move Ordering
  • PV-Move
  • Countermove Heuristic
  • History Heuristic
  • Killer Heuristic
  • Captures by MVV/LVA
  • Captures by Static Exchange Evaluation

Evaluation

• Tapered Eval
• Material
• Mobility
  • Bad Bishop
  • Rooks on (Semi) Open Files
• Pawn Structure
  • Pawn Hash Table
  • Isolated Pawns
  • Doubled Pawns
  • Backward Pawns
  • Passed Pawns
• King Safety
  • Pawn Shelter
  • Pawn Storms
  • Enemy Attacks
• Tempo Bonus

Forum Posts

• Lazy SMP >4 Thread Slowdown by Can Cetin, CCC, November 29, 2017
• Re: Parallel search/LazySMP question by Can Cetin, CCC, December 18, 2017
• Re: SCTR 1.1d win64 by CMCanavessi, CCC, January 03, 2018
• Official Release of Ethereal 10.00 (Two-years Anniversary) by Andrew Grant, CCC, May 30, 2018
• Re: TCEC should reconsider the ban on Ethereal by Andrew Grant, CCC, July 18, 2018

External Links

• GitHub - cetincan0/Defenchess: Chess Engine
• Defenchess in CCRL 40/40
• Defenchess wins TCEC Division 4, Chessdom, January 06, 2018 » TCEC Season 11

References