Weiss

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[ Weiss and its satellite craters [1] Weiss,

an UCI compliant open source chess engine by Terje Kirstihagen, written in C, first released in November 2019 under the GPL 3 [2]. Weiss was initially based on Vice and is inspired by Ethereal, Stockfish and Demolito. It is part of the OpenBench testing framework [3]. Weiss had its tournament debut at TCEC Season 18 in May 2020.

Board Representation

• Dense Bitboard Board-Definition
• 8x8 Board
• Fancy Magic Bitboards
• PEXT Bitboards

Search

• Iterative Deepening
• Aspiration Windows
• Principal Variation Search
• Transposition Table
• Selectivity
  • Check Extensions
  • Late Move Reductions
  • Mate Distance Pruning
  • Null Move Pruning
  • Reverse Futility Pruning
  • Late Move Pruning
  • Razoring
  • Quiescence Search
  • Delta Pruning
• Move Ordering
  • Hash Move
  • Internal Iterative Deepening
  • MVV/LVA
  • Killer Heuristic
  • History Heuristic

Evaluation

• Tapered Eval
• Material
• Bishop Pair
• Piece-Square Tables
• Mobility
• Rook on (Half) Open File
• Pawn Structure
  • Passed Pawn
  • Isolated Pawn
• King Safety - Virtual Mobility
• Tempo
• Automated Tuning

Misc#

• Syzygy Bases using Fathom
• Perft

Forum Posts#

• Engine release: weiss by Terje Kirstihagen, CCC, November 19, 2019
• Re: New engine releases 2019 by Terje Kirstihagen, CCC, December 06, 2019
• Re: New engine releases 2020 by Terje Kirstihagen, CCC, January 07, 2020
• Re: New engine releases 2020 by Terje Kirstihagen, CCC, February 14, 2020
• Re: New engine releases 2020 by Terje Kirstihagen, CCC, April 25, 2020
• Re: New engine releases & news 2021 (Weiss 1.4) by Terje Kirstihagen, CCC, July 02, 2021

External Links#

Chess Engine#

• GitHub - GitHub - TerjeKir/weiss: Weiss - a UCI chess engine
• Weiss in CCRL 40/15

Misc#

• weiss - Wiktionary
• Weiss - Wiktionary
• weiß - Wiktionary
• white - Wiktionary
• Weiss from Wikipedia
• Weiss (crater) from Wikipedia
• Weiß – Wikipedia.de (German)
• White from Wikipedia
• Hvit – Wikipedia.no (Bokmål)
• Kvit – Wikipedia.nn (Nynorsk)
• Häns’che Weiss Quintett, Dutch TV, 1977, YouTube Video

Lineup: Häns’che Weiss, Lulu Reinhardt, Ziroli Winterstein, Titi Winterstein, Hojok Merstein

References#

1. ↑ Weiss (named after Austrian astronomer Edmund Weiss) and its satellite craters on the moon, Image by Андрей Щербаков, October 30, 2013, Wikimedia Commons
2. ↑ Engine release: weiss by Terje Kirstihagen, CCC, November 19, 2019
3. ↑ weiss/README.md at master · TerjeKir/weiss · GitHub

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