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Culture and Education

People and Computers Working Together to Develop the Denou Sen and the World Computer Shogi Championship

Takenobu Takizawa
Professor, Faculty of Political Science and Economics, Waseda University

The first Denou Sen (a competition between a professional shogi player and a computer shogi program) will take place in Spring 2016 and will be sponsored by the Japan Shogi Association and Dwango Co., Ltd. This new shogi match consists of two games between the winner of the first phase of the Eiou Sen tournament (final will take place in December 2015) and that of the Third Shogi Denou Tournament (November 2015) with the former having the first move in one and the second move in the other. The Eiou Sen and the Shogi Denou Sen tournaments are knockout tournaments among professional shogi players and computer shogi programs, respectively.

Here I will provide historical background of competitions between professional shogi players and computer shogi programs. For technical information on shogi programs, refer to documents [1] and [2]. In this article, ranks and other information regarding professional shogi players refer to player information when matches took place.

In the special game of the First Daiwa Securities Cup tournament on March 21, 2007, Bonanza, a program developed by Kunihito Hoki, competed against Ryuo Akira Watanabe. At the end of the match, Ryuo Watanabe won by moving a ryu (dragon king or promoted rook) in the 39(third file, ninth rank) position (illustrated in Figure 1 onward). High-ranking professional shogi players are able to read this move before it is actually made, but it is the type of move that it is difficult for computer programs to predict. Ryuo Watanabe said that he was lucky to get such winning position, but it was most likely his abilities that earned him the victory.

Figure 1 Special Game of the Daiwa Securities Cup between ▲Bonanza and △Ryuo Akira Watanabe on March 21, 2007

In the First Shogi Denou Sen held on January 14, 2012, Lifetime Kisei Kunio Yonenaga, the president of the Japan Shogi Association at that time (who passed away on December 18, 2012), competed against the computer shogi program "Bonkras" developed by Eiki Ito. The computer program Bonkras defeated Yonenaga. In response to Bonkras’ first move with a fu (pawn) to position 76, Lifetime Kisei Yonenaga moved the gyoku (king) to position 62 (Figure 2), a strategy to hold down the first move’s offensive. Kunihitio Hoki suggests that the aim of this second move of placing the gyoku at position 62 suggested is to upset the opponent by making a move early in the match not often made by professional shogi players. In the end, Yonenaga’s strategy failed, but one would assume his strategy would be effective against a program that automatically evaluates its decisions against past data.

Figure 2 First Denou Sen between △Bonkras and ▲Lifetime Kisei Kunio Yonenaga on January 14, 2012

The second Shogi Denou Sen was from March 23 to April 20, 2013 and consisted of one game between a professional shogi player and a computer shogi program each week. The professional shogi player won the first game, but the computer shogi program achieved comeback victories against the professional shogi player in the final phases of the second and third games. In the fourth game, 9-dan Tsukada, who thought he would have no chance of winning if he approached the game in a normal way, shifted halfway through the game to a strategy aimed at a draw by bringing to jishogi. Professional shogi players who were watching the game in the waiting room insisted that Tsukada should admit defeat, but ultimately, as the 230th move was made, the game was declared jishogi, a draw (Figure 3). In the fifth game, the computer program defeated 8-dan Miura, a top-ranking professional shogi player.

Figure 3 The Second Denou Sen between ▲Puella α and △ Ninth-dan Yasuaki Tsukada on April 13, 2013

The Third Shogi Denou Sen was from March 15 to April 12, 2014 and consisted of one game between a professional shogi player and a computer shogi program each week. The rule was that while computer programs could not be modified after they were submitted for the First Denou Tournament in November 2013, professional shogi players were under no such restrictions when competing against the computer programs, which meant that it was a kind of handicap match. The professional shogi player won the fourth game but an overall record of one victory to four defeats. After the five games, President Koji Tanigawa of the Japan Shogi Association commented that it was safe to say that the computer program had abilities comparable to those of middle-level professional shogi players.

The Final Shogi Denou Sen was from March 14 to April 11, 2015 and consisted of one game between a professional shogi player and a computer shogi program each week. As in the third Shogi Denou Sen, the match was also handicapped. The professional shogi player won the first and second games and the computer program won the third and fourth games. The professional shogi player was victorious in the final game and the match by three wins and two losses, marking it their first victory in the Denou Sen series. Figure 4 indicates the position in the fifth game played between 8-dan Chikara Akutsu and computer program Awake (developed by Mr. Ryoichi Kose), in which the professional shogi player made the 21st move, moving a kyo (lance) on position 16. After the game progressed from this position for some time, Awake’s kaku (bishop) was captured when it invaded its opponent’s territory. If an amateur player had gone first, it would have been extremely difficult for him or her to win even from this position, but shogi program developer Kose commented that the professional player would easily win since he moved first.

Figure 4 Denou Sen Final between ▲Eighth-dan Chikara Akutsu and △Awake on April 11, 2015.

Looking back on the Denou Sen series since 2013, we can assume that because the 2015 team of professional players were young, promising players, and 6-dan Akira Nishio with his deep knowledge of computer shogi programs offered his support, the professional players were able to take advantage of the program that was lent out in advance by making appropriate preparations and utilizing counter strategies. This suggests that it is difficult even for professional shogi players to defeat computer shogi programs unless they are thoroughly prepared. Shogi computer programs also demonstrated their formidable capabilities and untapped potential.(Tables 1 and 2).

Table 1 Brief History of Computer Shogi
Year   Event
1949 The first article on computer chess was published.
Around 1950 The development of computer chess programs began.
1974   Takenobu Takizawa and his research group started developing computer shogi programs that were based on the minimax principle.
1984 Takizawa’s program played against the then Elementary School Student Meijin Yoshiyuki Kubota (currently 6-dan professional player). The program was completely defeated and evaluated as 5-kyu.
1986   Yoshiyuki Kotani, T. Takizawa, and other researchers established the Association of Computer Shogi Programmers (which was renamed the Computer Shogi Association in 1987).
1990   The First Computer Shogi Championship was held.
Around 1995   The strongest computer program reached the level of one-dan amateur players.
1996 Deep Blue won one victory over the world chess champion according to tournament rules.
1997 Deep Blue defeated the world chess champion according to tournament rules with two victories, one defeat, and three draws.
2002   Yoshimasa Tsuruoka won a championship using the search algorithm based on realization probability for his Gekisashi software program.
2005 Gekisashi ranked among the best 16 in the national amateur Ryuo tournament.
TACOS, which was developed by Tsuyoshi Hashimoto and his colleagues, played against 5-dan Takanori Hashimoto without a handicap and put up a tough fight. The Japan Shogi Association prohibited professional shogi players from competing against computer programs publicly.
2006   Kunihito Hoki was victorious using the automatic learning of parameters of evaluation functions and full-width search for his Bonanza software program.
2007 Bonanza played against Ryuo Akira Watanabe without a handicap and put up a good battle.
2009   Kunihito Hoki disclosed the source code of Bonanza to the public.
2010 The computer shogi system Akara 2010 defeated Joryu Osho Ichiyo Shimizu.
2012 Bonkras defeated Lifetime Kisei Kunio Yonenaga.
2013 Computer shogi programs played against professional shogi players, having three victories, one defeat, and one draw.
2014 Computer shogi programs played against professional shogi players, having four victories and one defeat..
2015 Computer shogi programs played against professional shogi players, having two victories and three defeats.

☆Game against an amateur player, ★Game against a professional player, ▼Computer chess

Table 2 Results of Matches between Professional Shogi Players and Computer Shogi Programs
Date(s) Match Professional shogi player Computer shogi program Time limit (in hours)
2007.3.21 Special game of the First Daiwa Securities Cup ○Akira Watanabe ●Bonanza (moving first) 2
2012.1.14 First Shogi Denou Sen ●Kunio Yonenaga ○Bonkras (moving first) 3
2013.3.23 Second Shogi Denou Sen ○Koru Abe (moving first) ●Shuso 4
2013.3.30 Second Shogi Denou Sen ●Shinichi Sato ○ponanza (moving first) 4
2013.4.6 Second Shogi Denou Sen ●Kohei Funae (moving first) ○Tsutsukana 4
2013.4.13 Second Shogi Denou Sen △Yasuaki Tsukada △Puella α(moving first) 4
2013.4.20 Second Shogi Denou Sen ●Hiroyuki Miura (moving first) ○GPS Shogi 4
2013.12.31 Revenge match ○Kohei Funae (moving first) ●Tsutsukana 4
2014.3.15 Third Shogi Denou Sen ●Tatsuya Sugai (moving first) ○Shuso 5*
2014.3.22 Third Shogi Denou Sen ●Shinya Sato ○Yaneurao (moving first) 5*
2014.3.29 Third Shogi Denou Sen ○Masayuki Toyoshima (moving first) ●YSS 5*
2014.4.5 Third Shogi Denou Sen ●Taku Morishita ○Tsutsukana (moving first) 5*
2014.4.12 Third Shogi Denou Sen ●Nobuyuki Yashiki (moving first) ○ponanza 5*
2014.7.19~7.20 Revenge match ●Tatsuya Sugai (moving first) ○Shuso 8*
2014.12.31~2015.1.1 Revenge match ○Taku Morishita ●Tsutsukana (moving first) 3★
2015.3.14 Shogi Denou Sen Final ○Shintaro Saito (moving first) ●Apery 5*
2015.3.21 Shogi Denou Sen Final ○Takuya Nagase ●Selene (moving first) 5*
2015.3.28 Shogi Denou Sen Final ●Akira Inaba (moving first) ○Yaneurao 5*
2015.4.4 Shogi Denou Sen Final ●Yasuaki Murayama ○ponanza (moving first) 5*
2015.4.11 Shogi Denou Sen Final ○Chikara Akutsu (moving first) ●AWAKE 5*

Professional shogi player vs computer shogi program (60-second countdown ((*) ten-minute countdown); ★ chess clock)

Professional shogi players proactively use shogi programs to study tactics and strategies. Going forward they are expected to be used by professional shogi players even more effectively for purposes such as verifying how to make moves based on new patterns. Developers are extremely grateful for professional players’ cooperation in the development of the programs.

Leading algorithms such as search algorithms based on realization probability (developed by Dr. Yoshimasa Tsuruoka and first used for Gekisashi) and the Bonanza Method (developed by Dr. Kunihito Hoki) were developed from studies of computer shogi programs. In 2009, Dr. Hoki disclosed the source code of Bonanza to the public, prompting rapid research in computer shogi programs, a trend that continues to this day.

The 25th World Computer Shogi Championship took place at the Kazusa Arc in Kisarazu, Chiba prefecture, from May 3 to 5, 2015, and was sponsored by the Computer Shogi Association. Even for the professional shogi players that provided commentary, the computer programs provided valuable insights.

A total of 39 teams, including two from overseas, participated in the three-day championship tournament. In this tournament, ponanza, developed by Issei Yamamoto and others, which defeated professional shogi players in three consecutive matches of the Denou Sen series, won its first victory in the seventh championship it participated in (Table 3). The 26th World Computer Shogi Championship will be held at the Kawasaki Sangyo Shinko Hall in Kawasaki, Kanagawa prefecture, from May 3 to 5, 2016.

Table 3 Overview of the World Computer Shogi Championship
Series Date(s) Venue Number of participants Winner Runner-up Third place
1 1990.12.2 Shogi Kaikan 6 Eisei Meijin Kakinoki Morita
2 1991.12.1 Shogi Kaikan 9 Morita Kiwame Eisei Meijin
3 1992.12.6 Shogi Kaikan 10 Kiwame Kakinoki Morita
4 1993.12.5 Shogi Kaikan 14 Kiwame Kakinoki Morita
5 1994.12.4 Sheraton 22 Kiwame Morita YSS
6 1996.1.20-21 Sheraton 25 Kanazawa Kakinoki Morita
7 1997.2.8-9 Sheraton 33 YSS Kanazawa Kakinoki
8 1998.2.12-13 Sheraton 35 IS Kanazawa Shotest
9 1999.3.18-19 Sheraton 40 Kanazawa YSS Shotest
10 2000.3.8-10 Sheraton 45 IS YSS Kawabata
11 2001.3.10-12 Kazusa 55 IS Kanazawa KCC
12 2002.5.3-5 Kazusa 51 Gekisashi IS KCC
13 2003.5.3-5 Kazusa 45 IS YSS Gekisashi
14 2004.5.2-4 Kazusa 43 YSS Gekisashi IS
15 2005.5.3-5 Kazusa 39 Gekisashi KCC IS
16 2006.5.3-5 Kazusa 43 Bonanza YSS KCC
17 2007.5.3-5 Kazusa 40 YSS Tanase Gekisashi
18 2008.5.3-5 Kazusa 40 Gekisashi Tanase Bonanza
19 2009.5.3-5 Waseda 42 GPS Otsuki Monju
20 2010.5.2-4 UEC 43 Gekisashi Shueso GPS
21 2011.5.3-5 Waseda 37 Bonkras Bonanza Shueso
22 2012.5.3-5 UEC 42 GPS Puella alpha Tsutsukana
23 2013.5.3-5 Waseda 40 Bonanza ponanza GPS
24 2014.5.3-5 Kazusa 38 Apery ponanza YSS
25 2015.5.3-5 Kazusa 39 ponanza NineDayFever AWAKE

Kanazawa is the successor of Kiwame.
Puella α is the successor of Bonkras.

Shogi Kaikan: Tokyo Shogi Kaikan
Sheraton: Sheraton Grande Tokyo Bay Hotel
Kazusa: Kazusa Akademia Hall
Waseda: Waseda University
UEC: University of Electro-Communications

Takenobu Takizawa
Professor, Faculty of Political Science and Economics, Waseda University

Profile
Born in November 1951

March 1974: Graduated from the Department of Mathematics, School of Science and Engineering, Waseda University
March 1977: Completed the Master’s Program in Mathematics, Graduate School of Science and Engineering, Waseda University
March 1980: Withdrew from the Doctoral Program in Mathematics, Graduate School of Science and Engineering, Waseda University after completing the course requirements.
April 1978: Assistant, Faculty of Engineering, Tamagawa University
April 1981: Full-Time Lecturer, Faculty of Engineering, Tamagawa University
April 1985: Full-Time Lecturer, School of Political Science and Economics, Waseda University
April 1987: Associate Professor, School of Political Science and Economics, Waseda University
April 1992: Professor, School of Political Science and Economics, Waseda University
April 2004–Present: Professor, Faculty of Political Science and Economics, Waseda University

Professor Takizawa's major publications (co-authored) include:
How to Make Computer Shogi Program [Ningen ni katsu Computer Shogi no Tsukurikata] (Gijutsu-Hyoron-Sha, November 2012, in Japanese, [1]),
Introduction to Fuzzy Theory and Its Application [Faji Riron—Kiso to Oyo—] (Kyoritsu Shuppan, August 2010, in Japanese),
Elementary Calculus for Economics [Keizaikei no Tameno Bibun Sekibun] (Kyoritsu Shuppan, March 2007, in Japanese)

Yomiuri Online
"How to Think Ahead of the Next Move of 'Akara': the Challenges of Computer Shogi"
Science: Opinion: Education x Waseda Online, November 29, 2010, [2].