Computer shogi is a field of artificial intelligence concerned with the creation of computer programs which can play shogi. The research and development of shogi software has been carried out mainly by freelance programmers, university research groups and private companies.
- 1 Game complexity
- 2 Computers versus humans
- 3 Programmer tools
- 4 Computer shogi programs
- 5 Restrictions
- 6 Milestones
- 7 See also
- 8 Notes
- 9 External links
Shogi has the distinctive feature of reusing captured pieces. Therefore shogi has a higher branching factor than other chess variants. The computer has more positions to examine because each piece in hand can be dropped on many squares. This gives shogi the highest number of legal positions and the highest number of possible games of all the popular chess variants. The higher numbers for shogi mean it is harder to reach the highest levels of play. The number of legal positions and the number of possible games are 2 measures of shogi’s Game complexity.
|Game||Board Size||Number of Pieces||Number of Different Pieces||Legal Positions||Possible Games||Average Game Length|
|Go / Baduk / Wei-qi||361||Up to 360||1||10171||10360||150|
Computers versus humans
In the 1980s, due to the immaturity of the technology in such fields as programming, CPUs and memory, computer shogi programs took a long time to think, and often made moves for which there was no apparent justification. These programs had the level of an amateur of kyu rank.
In the first decade of the 21st century, computer shogi has taken large steps forward in software and hardware technology. In 2007 top shogi player Yoshiharu Habu estimated the strength of the 2006 world computer shogi champion Bonanza. He contributed to the newspaper Nihon Keizai Shimbun evening edition on March 26, 2007 about the match between Bonanza and then Ryūō Champion Akira Watanabe. Habu rated Bonanza’s game at the level of 2 dan shoreikai.
In particular, computers are most suited to brute-force calculation, and far outperform humans at the task of finding ways of checkmating from a given position, which involves many fewer possibilities. In games with time limits of 10 seconds from the first move, computers are becoming a tough challenge for even professional shogi players. The past steady progress of computer shogi is a guide for the future. In 1996 Habu predicted a computer would beat him in 2015. Akira Watanabe gave an interview to the newspaper Asahi Shimbun in 2012. He estimated the computer played at the 4 dan professional level. Watanabe also said the computer sometimes found moves for him.
On 23 October 2005, at the 3rd International Shogi Forum, the Japan Shogi Association permitted Toshiyuki Moriuchi, 2005 Meijin, to play computer shogi program YSS. Toshiyuki Moriuchi won the game playing 30 seconds per move with a Bishop handicap. In 2012, a retired professional lost a match with computer publicly first, and in 2013, active shogi professionals too.
Bonanza vs Watanabe (2007)
The Japan Shogi Association (JSA) gave reigning Ryuo Champion Watanabe permission to compete against the reigning World Computer Shogi Champion Bonanza on 21 March 2007. Daiwa Securities sponsored the match. Hoki Kunihito wrote Bonanza. The computer was an Intel Xeon 2.66 GHz 8 core with 8 gigabytes of memory and 160-gigabyte hard drive. The game was played with 2 hours each and 1 minute byo-yomi per move after that. Those conditions favor Watanabe because longer time limits mean there are fewer mistakes from time pressure. Longer playing time also means human players can make long-term plans beyond the computer’s calculating horizon. The 2 players were not at the same playing level. Watanabe was 2006 Ryuo Champion and Bonanza was at the level of 2 dan shoreikai. Bonanza was a little stronger than before due to program improvements and a faster computer. Watanabe prepared for a weaker Bonanza as Watanabe studied old Bonanza game records.
Bonanza moved first and played fourth file rook anaguma as Watanabe expected. Watanabe thought some of Bonanza’s moves were inferior. However, Watanabe deeply analyzed these moves thinking that maybe the computer saw something that Watanabe did not see. Watanabe commented after the game that he could have lost if Bonanza had played defensive moves before entering the endgame. But the computer choose to attack immediately instead of taking its time (and using its impressive endgame strategies) which cost it the match. Bonanza resigned after move 112. Hidetchi reviews this game.
After Bonanza’s loss Watanabe commented on computers in his blog, “I thought they still had quite a way to go, but now we have to recognize that they’ve reached the point where they are getting to be a match for professionals.” Ryuo champion Akira Watanabe clarifies his position on computers playing shogi. Yomiuri Shimbun newspaper quoted Akira Watanabe on June 27, 2008. Watanabe said "I think I'll be able to defeat shogi software for the next 10 years". Another indication Bonanza was far below the level of professional Watanabe came 2 months after the match at the May 2007 World Computer Shogi Championship. Bonanza lost to the 2007 World Computer Shogi Champion YSS. Then YSS lost to amateur Kato Yukio in a 15-minute game.
Annual CSA tournament exhibition games (2003–2009)
The winners of CSA tournaments played exhibition games with strong players. These exhibition games started in 2003.
|2003||IS Shogi||Pro 5 Dan Katsumata||2 Piece Handicap||25 Min||None||Computer|
|2004||YSS||Pro 5 Dan Katsumata||Rook||25 Min||None||Computer|
|2005||Gekisashi||Pro 5 Dan Katsumata||Bishop||25 Min||None||Computer|
|2006||Bonanza||Yukio Kato||None||15 Min||30 Sec||Human|
|2007||YSS||Yukio Kato||None||15 Min||30 Sec||Human|
|2008||Tanase Shogi||Yukio Kato||None||15 Min||30 Sec||Computer|
|2008||Gekisashi||Shimizugami Toru||None||15 Min||30 Sec||Computer|
|2009||GPS Shogi||Amateur champion||None||1 hour||1 min||Canceled|
In each succeeding year, the human competition was stronger to match the stronger programs. Kato Yukio was the Asahi Amateur Meijin champion. Shimizugami Toru was the Amateur Meijin champion. Eiki Ito, the creator of Bonkras, said in 2011, at present, top Shogi programs like Bonkras are currently at a level of lower- to middle-class professional players.
Akara vs Shimizu (2010)
The Computer program Akara defeated the women’s Osho champion Shimizu Ichiyo. Akara contained 4 computer engines, Gekisashi, GPS Shogi, Bonanza and YSS. Akara ran on a network of 169 computers. The 4 engines voted on the best moves. Akara selects the move with the most votes. If there is a tie vote then Akara selects Gekisashi’s move. Researchers at the University of Tokyo and the University of Electro-Communications developed Akara.
Shimizu moved first and resigned in 86 moves after 6 hours and 3 minutes. Shimizu said she was trying to play her best as if she was facing a human player. She played at the University of Tokyo on 11 October 2010. The allotted thinking time per player is 3 hours and 60 seconds byoyomi. 750 fans attended the event. This is the third time since 2005 that the Japan Shogi Association granted permission to a professional to play a computer, and the first victory against a female professional. Hidetchi reviews this game.
Akara aggressively pursued Shimizu from the start of the game. Akara played with a ranging rook strategy and offered an exchange of bishops. Shimizu made a questionable move partway though the game, and Akara went on to win. Ryuo champion, Akira Watanabe, criticized Shimizu’s game. On 19 November 2010, the Daily Yomiuri quoted Watanabe. Watanabe said, "Ms. Shimizu had plenty of chances to win".
Computers Bonanza and Akara beat Amateurs Kosaku and Shinoda (2011)
On July 24, 2011, there was a two game amateur versus computer match. Two computer Shogi programs beat a team of two amateurs. One amateur, Mr. Kosaku, was a Shoreikai three Dan player. The other amateur, Mr. Shinoda, was the 1999 Amateur Ryuo. The allotted time for the amateurs was main time 1 hour and then 3 minutes per move. The allotted time for the computer was main time 25 minutes and then 10 seconds per move.  
|Game||Computer||Sente (first)||Gote (second)||Moves||Computer Time||Amateur Time||Hardware||Winner|
|1||Bonanza||Kosaku & Shinoda||Bonanza||93||24 min 41 sec||2 hours 2 min||17 processors, 132 cores, 300 GB||Bonanza|
|2||Akara||Akara||Kosaku & Shinoda||150||25 min 54 sec||1 hour 42 min||Intel Xeon W3680 with 6 cores||Akara|
Bonkras versus Yonenaga (2011–2012)
On 21 December 2011, computer program Bonkras crushed retired 68 year old Kunio Yonenaga, the 1993 Meijin. They played 85 moves in 1 hour, 3 minutes 39 seconds on Shogi Club 24. Main time was 15 minutes then additional 60 seconds per move. Yonenaga was gote (white) and played 2. K-62. This move was to confuse the computer by playing a move not in Bonkras's joseki (opening book). On 14 January 2012, Bonkras again defeated Yonenaga. The game had 113 moves. Time allowed was 3 hours and then 1 minute per move. Bonkras moved first and used a ranging rook opening. Yonenaga made the same second move, K-6b, as in the previous game he lost. Bonkras ran on a Fujitsu Primergy BX400 with 6 blade servers to search 18,000,000 moves per second. Yonenaga used 2 hours 33 minutes. Bonkras used 1 hour 55 minutes. Bonkras evaluated its game with Yonenaga in January 2012.
Denou-sen is a human versus machine battle. Niconico is sponsoring 5 games. 5 professional shogi players play 5 computers. The winners of the previous World Computer Shogi Championship play the professional shogi players. Each player starts with 4 hours. After the player finishes 4 hours, the player must complete each move in 60 seconds. Niconico is broadcasting the games live with commentary.
Programs Program Programmers Hardware Positions/second Moves deep Programmer's First Tournament Shueso Akira Takeuchi 2 CPUs/8 cores 10,000,000 18~ 2008 Ponanza Issei Yamamoto 10 CPUs 30,000,000 30~ 2009 Tsutsukana Takanori Ichimaru 1 CPU 2010 Puella alpha Eikyu Ito 3 CPUs/16 cores 4,000,000 20~ 1999 GPS Shogi Tanaka Tetsuro, GPS team 667 CPUs 280,000,000 22 2001
Games Date Sente Black 1st Gote White 2nd Moves Professional Time Computer Time Winner March 23 Abe Kouru Shueso 113 3 hours, 1 minute 3 hours, 15 minutes Human March 30 Ponanza Sato Shinichi 141 3 hours, 59 minutes 3 hours, 31 minutes Computer April 6 Funae Kouhei Tsutsukana 184 3 hours, 59 minutes 3 hours, 27 minutes Computer April 13 Puella Alpha Tsukada Yasuaki 230 3 hours, 29 minutes 2 hours, 19 minutes Draw April 20 Miura Hiroyuki GPS Shogi 102 3 hours, 59 minutes 2 hours, 7 minutes Computer
Miura Hiroyuki vs GPS Shogi
Hiroyuki Miura said before his game he would play with "all his heart and soul". Miura decided to use trusted tactics instead of anti-computer strategy. The computer played book moves and they castled symmetrically to defend their kings. The computer attacked quickly and Miura counterattacked with a drop move. More than 8 hours later Miura resigned. After the game, Miura said that "he should not have prepared for the game the way he did. He should have prepared for the game with a genuine sense of urgency, if only he knew, the computer was so strong."
Shogidokoro is a graphical user interface (GUI) that calls a program to play shogi and displays the moves on a board. Shogidokoro was created in 2007. Shogidokoro uses the Universal Shogi Interface (USI). The USI is an open communication protocol that Shogi programs use to communicate with a user interface. USI was designed by Norwegian computer chess programmer Tord Romstad in 2007. Tord Romstad based USI on Universal Chess Interface (UCI). UCI was designed by computer chess programmer Stefan Meyer-Kahlen in 2000. Shogidokoro can automatically run a tournament between 2 programs. This helps programmers to write shogi programs faster because they can skip writing the user interface part. It is also useful for testing changes to a program. Shogidokoro can be used to play Shogi by adding a Shogi engine to shogidokoro. Some engines that will run under shogidokoro are Blunder, GPS Shogi, Laramie, Lightning, ponanza, Spear, Ssp and TJshogi. Bonanza can also run with an adapter (u2b).
WinBoard/XBoard and BCMShogi
WinBoard/XBoard and BCMShogi are other GUIs that support Shogi. This support was added to WinBoard in 2007 by H.G. Muller. WinBoard uses its own protocol (Chess Engine Communication Protocol) to communicate with engines, but can connect to USI engines through the UCI2WB adapter. Engines that can natively support WinBoard protocol are Shokidoki, TJshogi, GNU Shogi and Bonanza. Unlike Shogidokoro, WinBoard is open source, and also available under Linux as XBoard. BCMShogi is a graphical user interface for the USI protocol and the WinBoard shogi protocol.
Floodgate is a computer shogi server for computers to compete and receive ratings. Programs running under Shogidokoro can connect to Floodgate. The GPS team created Floodgate. Floodgate started operating continuously in 2008. The most active players have played 4,000 games. From 2008 to 2010, 167 players played 28,000 games on Floodgate. Humans are welcome to play on Floodgate. The time limit is 15 minutes per player, sudden death.
Floodgate Annual Highest Rating Date Program Rating May 23, 2011 Bonanza_expt 3054 May 23, 2012 PonanzaCluster 3080 May 23, 2013 Ponanza_expt 3113
World Computer Shogi Championship
The annual computer vs computer world shogi championship is organized by the Computer Shogi Association (CSA) of Japan. The computers play automated games through a server. Each program has 25 minutes to complete a game. The first championship was in 1990 with 6 programs. In 2001, it grew to 55 programs. The championship is broadcast on the Internet. At the 19th annual CSA tournament, 4 programs (GPS Shogi, Otsuki Shogi, Monju and KCC Shogi) that had never won a CSA tournament defeated 3 of the previous year’s strongest programs (Bonanza, Gekisashi and YSS). The top three winners of the 2010 CSA tournament are Gekisashi, Shueso and GPS Shogi.
In 2011, Bonkras won the CSA tournament with 5 wins out of 7 games. Bonkras ran on a computer with 3 processors containing 16 cores and 6 gigabytes of memory. Bonanza won second place on a computer with 17 processors containing 132 cores and 300 gigabytes of memory. Shueso won third place. The 2010 CSA winner, Gekisashi, won fourth place. Ponanza won fifth place. GPS Shogi won 6th place on a computer with 263 processors containing 832 cores and 1486 gigabytes of memory. In 2012, GPS Shogi searched 280,000,000 moves per second and the average search depth was 22.2 moves ahead.
|1||1990||Nobuhiro Yoshimura||Eisei Meijin||5/5||NEC PC-9801RA21|
|2||1991||Kazurou Morita||Morita Shogi 3||7/8||NEC PC-H98S||ASM|
|3||1992||Log corp.||Kiwame||5/7||486DX2||66 MHz||C|
|4||1993||Log corp.||Kiwame II||7/7||Pentium||60 MHz||C|
|5||1994||Shinichirou Kanazawa||Kiwame 2.1||6/7||Pentium||90 MHz||C|
|6||1996||Shinichirou Kanazawa||Kanazawa Shogi||7/7||Alpha AXP||300 MHz||C|
|7||1997||Hiroshi Yamashita||YSS 7.0||7/7||Alpha||500 MHz||C|
|8||1998||Yasushi Tanase||IS Shogi||6/7||Pentium II||300 MHz||C|
|9||1999||Shinichirou Kanazawa||Kanazawa Shogi||6/7||Pentium III||500 MHz||C|
|10||2000||Yasushi Tanase||IS Shogi||5/7||Athlon||800 MHz||C|
|11||2001||Yasushi Tanase||IS Shogi||9/9||Athlon||1.2 GHz||C|
|12||2002||University of Tokyo||Gekisashi||6/7||Athlon MP *2||2000+||C++|
|13||2003||Yasushi Tanase||IS Shogi||6/7||Pentium 4||3.00 GHz||C++|
|14||2004||Hiroshi Yamashita||YSS 7.0||6/7||Opteron 248 *2||2.2 GHz||C++|
|15||2005||Gekisashi Team||Gekisashi||7/7||Opteron *2||2.6 GHz||C++|
|16||2006||Kunihito Hoki||Bonanza||6/7||CoreDuo T2600||2.16 GHz||C|
|17||2007||Hiroshi Yamashita||YSS 7.0||6/7||Xeon X5355||2.66 GHz||2||8||C++|
|18||2008||Gekisashi Team||Gekisashi||6/7||Xeon X5482||3.2 GHz||2||8||C++|
|19||2009||GPS Team||GPS Shogi||6/7||Xeon X5570||2.93 GHz||2||8||C++|
|20||2010||Gekisashi Team||Gekisashi||6/7||Xeon W5590||3.33 GHz||2||8||C++|
|21||2011||Eikyu Ito||Bonkras||5/7||Core i7-980, Core i7-2600K, PhenomIIX6 1100T||3.4 GHz 3.4 GHz 3.33 GHz||3||16||6 GB||C, C + +|
|22||2012||GPS Team||GPS Shogi||6/7||Cluster 797 computers||804||3224||3272 GB||C++|
|23||2013||Kunihito Hoki||Bonanza||5/7||Xeon (Multi)||31||388||C, Perl|
Computer shogi programs
Components of computer shogi programs:
- Opening book : An opening book of moves puts the program in a good position and saves time. The problem is professionals do not always follow an opening sequence as in chess but make different moves to create good formation of pieces.
- Search algorithm : The Search algorithm that looks ahead more deeply in a sequence of moves allows the program to better evaluate a move. The search is harder in shogi than in chess because of the larger number of possible moves. A program will stop searching when it reaches a stable position. The problem is many positions are unstable because of the drop move.
- Endgame : The endgame starts when the king is attacked and ends when the game is won. In chess there are fewer pieces which leads to perfect play by endgame databases. In shogi pieces can be dropped so there are no endgame databases. A Tsumeshogi solver is used to quickly find mating moves.
Computer shogi programs that have played at the annual World Computer Shogi Championships:
- Bonanza won first place in 2013 and at its first entry in the championships in 2006. Programmer Kunihito Hoki was living in Canada.
- YSS won in 1997, 2004 and 2007. YSS won 2nd place in 1999, 2000, 2003, 2006 and 3rd place in 1994. Programmer is Hiroshi Yamashita. YSS entered the first time in the 1991 tournament.
- IS Shogi won in 1998, 2000, 2001 and 2003. Yasushi Tanase was part of the Tokyo University team that wrote IS Shogi.
- Tanase shogi won 2nd place in 2007 and 2008 also written by Yasushi Tanase.
- Gekisashi won 2002, 2005, 2008 and 2010. The Gekisashi team is led by Yoshimasa Tsuruoka.
- KCC Shogi came in second place in 2005 and is from North Korea.
- Shogi Kakinoki won 2nd place in 1990, 1992, 1993 and 1996 and written by Yoshikazu Kakinoki.
- Kiwame won in 1992, 1993 and 1994 and written by Shinichirou Kanazawa.
- Shogi Kanazawa won in 1996 and in 1999 also written by Shinichirou Kanazawa.
- Morita Shogi won in 1991 and written by Kazurou Morita.
- Shotest won 3rd place in 1998, 1999 and written by British programmer Jeff Rollason.
- Spear a free program written by Reijer Grimbergen has won 9th place of 24 in the 2009 upper division contest.
- GPS Shogi is free software written by staffers and students of the University of Tokyo and won in 2009 and 2012.
Computer Shogi programs that play in video game systems:
- Habu Meijin no Omoshiro Shōgi plays on the Super Famicom.
- Clubhouse Games includes Shogi and plays on the Nintendo DS.
- Shotest Shogi plays on the Xbox.
- List of shogi video games.
GNU Shogi is a free software program by the Free Software Foundation that plays Shogi.
On 18 September 2005 a Japan Shogi Association professional 5 dan played shogi against a computer. The game was played at the 29th Hokkoku Osho-Cup Shogi Tournament in Komatsu, Japan. The Matsue National College of technology developed the computer program Tacos. Tacos played first and chose the static rook line in the opening. Professional Hashimoto followed the opening line while changing his bishop with the bishop of Tacos. Tacos had a good development with some advantages in the opening and middle game even until move 80. Many amateur players expected Tacos to win. However, professional Hashimoto defended and Tacos played strange moves. Tacos lost.
On 14 October 2005, the Japan Shogi Association banned professional shogi players from competing against a computer. The Japan Shogi Association said the rule is to preserve the dignity of its professionals, and to make the most of computer shogi as a potential business opportunity. The ban prevents the rating of computers relative to professional players. From 2008 to 2012, the Japan Shogi Association has not permitted any games between a male professional and a computer.
- 2005, At the Amateur Ryo tournament, program Gekisashi defeated Eiji Ogawa in a 40 minute game of the first knock out round.
- 2005, Program Gekisashi defeated amateur 6-dan Shinoda Masato in a 40 minute exhibition game.
- 2007, Highest rating for a computer on Shogi Club 24 is 2744 for YSS.
- 2008 May, computer program Tanase Shogi beat Asahi Amateur Meijin title holder Kato Yukio. 75 moves played in 15 minute exhibition game.
- 2008 May, computer program Gekisashi beat Amateur Meijin Shimizugami Toru. 100 moves played in 15 minute exhibition game.
- 2008 November, Gekisashi beat Amateur Meijin Shimizugami in a 1 hour game with 1 minute byoyomi.
- 2010 October, first time a computer beat a Shogi champion. Akara beat the women’s Osho champion Shimizu in 6 hours and 3 minutes.
- 2011 May, Highest rated player on Shogi Club 24 is computer program Ponanza, rated 3211.
- 2011 December, Highest rated player on Shogi Club 24 is computer program Bonkras, rated 3364 after 2116 games.
- 2012 January, Bonkras defeated the 1993 Meijin Yonenaga. They played 113 moves with main time 3 hours and then 1 minute per move.
- 2013 April 20, GPS Shogi defeated Miura Hiroyuki, ranked 15. Game was 102 moves with main time 4 hours then 1 minute per move.
- 2013 May 12, Highest rated player on Shogi Club 24 is computer program Ponanza, rated 3453.
- Shogi variant
- Computer Chess
- Computer Othello
- Computer Go
- Computer International Draughts
- Computer English Draughts
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- Computer versus Human Shogi Events in Japanese