Editing Shogi (section)

== Computer shogi ==
{{Main|Computer shogi}}

Shogi has the highest [[game tree complexity|game complexity]] of all popular chess variants. Computers have steadily improved in playing shogi since the 1970s. In 2007, champion Yoshiharu Habu estimated the strength of the 2006 world computer shogi champion Bonanza at the level of two-dan shoreikai.

The JSA prohibits its professionals from playing computers in public without prior permission, with the reason of promoting shogi and monetizing the computer–human events.<ref>{{cite news|title=Shogi pros warned not to play computers|url=http://www.japantimes.co.jp/text/nn20051016a4.html|access-date=28 November 2011|newspaper=[[The Japan Times]]|date=16 October 2005|location=Tokyo, Japan|archive-date=11 April 2020|archive-url=https://web.archive.org/web/20200411070426/https://www.japantimes.co.jp/text/nn20051016a4.html|url-status=dead}}</ref>

On October 12, 2010, after some 35 years of development, a computer finally beat a professional player, when the top ranked female champion Ichiyo Shimizu was beaten by the Akara2010 system in a game lasting just over 6 hours.<ref>{{cite news|url=http://www.japantimes.co.jp/news/2010/10/13/national/top-female-shogi-pro-falls-to-computer|title=Top female 'shogi' pro falls to computer|newspaper=Japan Times|agency=[[Kyodo]]|date=12 October 2010|access-date=17 December 2014}}</ref>

On July 24, 2011, computer shogi programs Bonanza and Akara crushed the amateur team of Kosaku and Shinoda in two games. The allotted time for the amateurs was one hour and then three minutes per move. The allotted time for the computer was 25 minutes and then 10 seconds per move.<ref>{{cite news|url=http://www.asahi.com/shougi/topics/TKY201108020334.html|newspaper=[[The Asahi Shimbun]]|title=Shōgi Sofuto ni Amagumi Kanpai: Hijutsu, Ikki ni Semetsubusareru|script-title=ja:将棋ソフトにアマ組完敗 秘術、一気に攻めつぶされる|trans-title=Shogi computer programs crush amateurs |date=2 August 2011|language=ja|access-date=17 December 2014}}</ref>

On April 20, 2013, GPS Shogi defeated 8-dan professional shogi player [[Hiroyuki Miura (shogi)|Hiroyuki Miura]] in a 102-move game which lasted over 8 hours.<ref>{{cite web |trans-title=Second Shogi Denosen, Game 5: Hiroyuki Miura 8 dan vs. GPS Shogi|title=Dainikai Shōgi Denōsen Daigokyoku Miura Hiroyuki vs GPS Shōgi|date=20 April 2013 |script-title=ja:第2回 将棋電王戦 第5局 三浦弘行八段 vs GPS将棋|url=http://live.nicovideo.jp/watch/lv118757933|publisher=Niwango |access-date=17 December 2014|language=ja}}</ref>

On December 13, 2015, the highest rated player on Shogi Club 24 was computer program Ponanza, rated 3455.<ref>{{cite web | url=http://www.shogidojo.com |title=Computer program Bonkras highest rated player on Shogi Club 24 |publisher=Shogi Club 24 |language=ja}}</ref>

On April 10, 2016, Ponanza defeated Takayuki Yamasaki, 8-dan in 85 moves. Takayuki used 7 hours 9 minutes.<ref>{{cite news|last1=Shinji|first1=Fukamatsu|title=AI beats top shogi player in first match of tournament final：The Asahi Shimbun|url=http://www.asahi.com/ajw/articles/AJ201604110029.html|access-date=17 May 2016|work=The Asahi Shimbun|language=en-us|archive-date=16 May 2016|archive-url=https://web.archive.org/web/20160516112047/http://www.asahi.com/ajw/articles/AJ201604110029.html|url-status=dead}}</ref>

In October 2017, [[DeepMind]] claimed that its program [[AlphaZero]], after a full nine hours of training, defeated [[Elmo (shogi engine)| Elmo]] in a 100-game match, winning 90, losing 8, and drawing two.<ref name=preprint>{{Cite arXiv|eprint=1712.01815|class=cs.AI |author=[[David Silver (programmer)|David Silver]] |author2=Thomas Hubert |author3=Julian Schrittwieser |author4=Ioannis Antonoglou |author5=Matthew Lai |author6=Arthur Guez |author7=Marc Lanctot |author8=Laurent Sifre |author9=[[Dharshan Kumaran]] |author10=Thore Graepel |author11=Timothy Lillicrap |author12=Karen Simonyan |author13=[[Demis Hassabis]] |title=Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm|date=5 December 2017}}</ref><ref>{{Cite news|url=https://www.theverge.com/2017/12/6/16741106/deepmind-ai-chess-alphazero-shogi-go|title=DeepMind's AI became a superhuman chess player in a few hours, just for fun|work=The Verge|access-date=2017-12-06}}</ref>

From a [[computational complexity theory|computational complexity]] point of view, generalized shogi is [[EXPTIME-complete]].<ref>{{cite journal |author1=H. Adachi |author2=H. Kamekawa |author3=S. Iwata | title = Shogi on n × n board is complete in exponential time | journal = Trans. IEICE | volume= J70-D | pages = 1843–1852 | year = 1987}}</ref>