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Fabian Fichter edited this page Jun 19, 2020 · 130 revisions

Overview

Fairy-Stockfish outperforms most chess variant engines, except for variants where many highly specialized engines exist (e.g., Shogi), and is the strongest engine in a variety of variants such as Janggi, Sittuyin, Capablanca chess, etc.

Chess

For standard chess, functionality is almost identical with official or multi-variant Stockfish, but the slowdown (>2x) due to overhead for fairy pieces and variants leads to >100 Elo weaker performance.

Lichess variants

For the variants supported by lichess and multi-variant Stockfish (Crazyhouse, antichess, 3check, etc.), playing strength is on par (+-200 Elo) with multi-variant Stockfish, and above other variant engines.

Fairy chess variants

For chess variants with fairy pieces (e.g., shatranj, makruk, sittuyin, etc.), playing strength is above all other known multi-variant engines (e.g., Sjaak II, FairyMax, Nebiyu) and at least on par with the best (non-Stockfish) engines in the respective variant, e.g., Bilis (makruk) or Shokidoki (minishogi), except for Shogi and Xiangqi, see below.

Janggi

For Janggi the playing strength of Fairy-Stockfish seems to be at least on par with professional players as well as strong engines (such as Janggidosa), see e.g. https://www.youtube.com/playlist?list=PLGE6rVolMRXZwprT9CQYz3CAvU2Y5zNnj.

Xiangqi

Playing strength in Xiangqi is slightly above the level of Elephant Eye and Cyclone 0.55, at least on master level.

Shogi

In shogi, playing strength is more than 1000 Elo below top engines using NN evaluation (such as YaneuraOu or apery using elmo evaluation), since it uses a simple handcrafted evaluation. Its playing strength in the shogi engine rating list (old) should be around 2500. Compared to human players it should be on the top amateur level. In shogi variants (minishogi, euroshogi, etc.), however, it seems to be the strongest available engine, e.g., winning the 11th UEC cup in minishogi, and is able to practically solve small-sized shogi variants such as dobutsu, micro, and kyoto shogi.

Compared to engine opponents

When no statistical uncertainty is specified, the estimate is derived from very few games (<100).

Normal version

variant relative elo reference engine
chess -120.67 +-13.9 MV-SF
crazyhouse -115.61 +-22.5 MV-SF
giveaway +184.42 +-21.7 MV-SF
3check -98.44 +-22.1 MV-SF
king of the hill -166.66 +-22.6 MV-SF
racing kings -85.78 +-17.1 MV-SF
horde -247.97 +-27.2 MV-SF
losers +24.36 +-20.8 MV-SF
extinction +515.19 +-50.7 MV-SF
placement +748.80 +-68.8 MV-SF
seirawan -152.60 +-20.5 Seirawan-Stockfish
shatranj -31.70 +-11.9 Shatranj-Stockfish
makruk +76.25 +-11.5 Makruk-Stockfish
makruk +300 +-100 Bilis v1.0
makruk +400 +-100 NebiyuChess 1.45
makruk >+400 Sjaak II
shatranj >+400 Tiyaga v1.0
shatranj >+400 Sjaak II
shatranj >+400 NebiyuChess 1.45
ASEAN >+400 Sjaak II
sittuyin >+400 Sjaak II
shatar >+400 Sjaak II
losalamos +600 Sjaak II
losalamos +700 NebiyuAlien 1.45
minishogi >+400 Sjaak II
minishogi +400 Crazywa
minishogi +250 Shokidoki ICGA15
minishogi +250 Lima v2-00
minishogi +200 Lima v4
euroshogi >+400 Sjaak II
euroshogi +400 Shokidoki ICGA15
breakthrough >+400 GameMaster 2.0

Large-board version

For variants that are also supported by the normal version (i.e., variants on boards <= 8x8), using the version for large boards decreases playing strength by 50-200 Elo due to lower speed and a few functional differences. Playing strength estimates for variants with large boards are given below.

variant relative elo reference engine
xiangqi +100 Cyclone 0.55
xiangqi +100 Elephant Eye 3.31
xiangqi +300 Sjaak II
xiangqi >+500 MaxQi
shogi <-1000 YaneuraOu using elmo
shogi <-1000 apery using elmo
shogi -400 apery wcsc26
shogi -100 Gikou 2 D9
shogi +100 Gikou 2 D8
shogi +300 apery (no eval file)
shogi +300 Shokidoki ICGA15
shogi >+400 Crazywa
shogi >+400 Sjaak II
capablanca +700 NebiyuChess 1.45
capablanca +700 Sjaak II

Compared to human opponents

Below is a list of mostly rough estimates about the playing strength compared to human level. Feel free to update this table if you have some information about a variant.

variant level
chess superhuman
crazyhouse superhuman
janggi superhuman
xiangqi master
shogi master
minishogi superhuman
makruk grandmaster/superhuman?
breakthrough master?