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a Chess Engine Communication Protocol compatible, free chess engine written in C++ by Philipp Claßen, supported by his brother Michael Claßen [1] . The name was taken from the name of Wolf Larsen's seal-hunting schooner in the novel The Sea-Wolf by Jack London.

Ghost started its life in about 2000 as subject of a school project, the first version appeared in early 2001, playing online at Internet Chess Club [2] , and later in rating list tournaments such as CCRL [3] . Subsequent versions were Ghost 1, Ghost 2, and Ghost 3. Executables are available for Windows and Linux platforms. Likely, the current Ghost is bitboard based, due to the much faster 64-bit executable.
Hammersmith Ghost [4]

Ghost 1

Ghost 1 performed NegaScout, IID, killer- and history heuristics, recursive null move pruning with depth reduction of 3, razoring and futility pruning, and a unique technique to detect perpetual checks. It further used the oracle approach of pre-scanned piece-square tables at the root [5] .

Ghost 2

The second version, first released in 2003, is a MTD(f) searcher, further utilizing late move reductions, adaptive null move pruning with R of 2 or 3 plies, ETC, and a unique pin detection extension. Ghost 2 has a safer perpetual check detection than Ghost 1, and usus local history counters [6] .

Ghost 3

Still using MTD(f), the search has been rewritten from scratch to support parallelism using work stealing provided by the Threading Building Blocks library. The stable version 3.1 was released on May 30, 2017 [7].

See also

Forum Posts

External Links

Chess Engine



  1. ^ Michael Claßen - Germany | LinkedIn
  2. ^ crafty vs ghost on ICC ...could Kasparov himself execute such an attack? by Jeffrey Wadsworth, CCC, October 28, 2001
  3. ^ Ghost 2.0.1 in CCRL 40/40
  4. ^ The image comes from Kirby's Wonderful and Scientific Museum, volume II, published in 1804 in London, Hammersmith Ghost murder case from Wikipedia
  5. ^ Ghost | Search algorithms: Ghost 1 by Philipp Claßen
  6. ^ Ghost | Search algorithms: Ghost 2 by Philipp Claßen
  7. ^ Ghost 3.1 released! by Günther Simon, CCC, June 01, 2017

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