Ōshō (王将 ōshō) is one of the eight titles in Japanese professional shogi. The tournament is co-sponsored by Sports Nippon and the Mainichi Shimbun with additional support received from the Igo & Shogi Channel[ja]. The tournament was first held in 1950 as a non-title tournament. The following year in 1951, it was elevated to major title status as the third major title along with the Meijin and Tenth Dan (later Ryūō) title tournaments.
There is a separate tournament held each year for amateurs called the Amateur Osho Tournament[ja] which is sponsored by the Japan Shogi Association with support from the Igo & Shogi Channel. The winner is awarded the title "Amateur Ōshō" (アマ王将 Ama Ōshō).
The word also refers to the piece called the "King" in shogi.
The tournament is open to all shogi professionals (正棋士 seikishi) and takes place in four stages. The first and second preliminary rounds consist of multiple single-elimination tournaments in which the first round winners advance to compete against each other in the second round. The three winners of the second round tournaments then advance to a round-robin league called the "challenger league (挑戦者決定リーグ戦 Chōsensha Kettei Rīgusen)" along with four seeded players. The winner of the challenger league then advances to a best-of-seven championship match against the reigning Ōshō title holder. If two players or more finish tied for first in the challenger league, a single-game playoff between the two highest seeded players is held to determine the challenger. The time controls are three hours per player for the two preliminary rounds, four hours per player for the challenger league, and eight hours per player for the championship match. The championship match is held from January to March.
The following is a list of the winners and runners-up for past Ōshō matches.
- Most titles overall: Yasuharu Oyama, 20
- Most consecutive titles: Yasuharu Oyama, 9 in a row (1963-1971)
"Lifetime Ōshō" (永世王将 Eisei Ōshō) is the title given to a player who has won the championship ten times. An active player may qualify for the title, but it is only officially awarded upon retirement or death. Yasuharu Oyama and Yoshiharu Habu are the only players who have qualified for this title: Oyama qualified in 1973 and Habu qualified for the title in 2007.
- "Kisen Jōhō Ōshōsen" 棋戦情報 王将戦 [Tournament Information: The Osho Tournament] (in Japanese). Japan Shogi Association. Retrieved April 1, 2015.
- "Shōgi Taikai: Zenkoku Amachua Ōshōi Taikai" 将棋大会 全国アマチュア王将位大会 [Shogi Tournaments: All Japan Amateur Osho Tournament] (in Japanese). Japan Shogi Association. Retrieved April 1, 2015.
- "Ōshōsen Gaiyō" 王将戦概要 [Osho Tournament Summary] (in Japanese). Japan Shogi Association. Retrieved April 1, 2015.
- "Ōshōsen Kako no Kekka" 王将戦過去の結果 [Osho Match past results] (in Japanese). Japan Shogi Association. Retrieved March 31, 2015.
- "Kubo Shin Ōshō Tanjō! Chōkyūsen o Gyakuten Shi, Kiō to Nikan"
[Kubo new Osho is crowned! Comes from behind to win very sharp game to hold two major titles at same time.]. Sports Nippon (in Japanese). March 18, 2010. Archived from the original on March 25, 2010. Retrieved December 19, 2017.
羽生善治王将(39)に久保利明棋王(34)が挑戦する第59期王将戦7番勝負の第6局...久保が超急戦を逆転勝利した。初の王将位を奪取して...[Toshiaki Kubo Kioh (age 34), challenger to Yoshiharu Habu Osho (age 39), comes from behind to win a very sharp Game 6 of the 7-game 59th Osho title to win Osho title for the first time.]
- "Kubo Ōshō ga Hatsu Bōei! Azayaka na Sabaki de Shōri"
[Kubo Osho defends title for the first time. Wins with brilliant technique]. Sports Nippon (in Japanese). March 16, 2011. Archived from the original on August 13, 2014. Retrieved December 19, 2017.
久保利明王将 (35) が勝ち, 通算成績4勝2敗で初防衛を果たした。[Toshiaki Kubo Osho (age 35) wins and defends title for the first time by a score of 4-2]
- "Satō Kudan ga Taitoru Dasshu, Shōgi Ōshōsen"
[Shogi Osho Match: Sato 9-dan captures title]. Asahi Shimbun (in Japanese). March 9, 2012. Retrieved March 31, 2015.
挑戦者の佐藤康光九段(42)が久保利明王将(36)に109手で勝って, 通算成績を4勝1敗とし, タイトルを奪取した。[Challenger Yasumitsu Sato 9-dan (age 42) defeats Toshiaki Kubo Osho (age 36) in 109 moves to win match 4-1 and capture the title.]
- "Dai Gokyoku, Watanabe Ryūō ga Ōshō Hatsudasshu, Nikan ni"
第5局, 渡辺竜王が王将初奪取, 2冠に
[Watanabe Ryu-oh wins Game 5 to capture Osho title for the first time and become a 2-crown]. Sankei Shimbun (in Japanese). March 7, 2013. Retrieved March 31, 2015.
124手で後手の渡辺竜王が勝ち, 対戦成績4勝1敗で初めて王将を奪取。[Challenger Watanabe Ryu-oh wins in 124 moves as gote to win match 4–1 and capture the Osho title for the first time.]
- Fukamatsu, Shinji (March 27, 2014). "Watanabe Ōshō ga Hatsubōei Shogi Ōshōsen, Habu Sankan Shirizokeru"
渡辺王将が初防衛 将棋王将戦, 羽生三冠退ける
[Shogi Osho Match: Watanabe Osho defends title for first time, defeats Habu 3-crown]. Asahi Shimbun (in Japanese). Archived from the original on April 1, 2013. Retrieved December 15, 2017.
渡辺明王将(29)が挑戦者の羽生善治三冠(43)に110手で勝ち, シリーズ4勝3敗で初防衛を果たした。[Akira Watanabe Osho (age 29) defeats challenger Yoshiharu Habu 3-crown (age 43) in 110 moves to win series 4-3 and defend title for the first time.]
- "Ōshōsen, Gōda Kudan ga Saishūkyoku Sesshi Hatsu Dasshu"
[Osho Match: Goda 9 dan wins final game to capture title for the first time]. Sankei Shimbun (in Japanese). March 27, 2015. Retrieved March 31, 2015.
挑戦者で先手の郷田真隆九段(44)が渡辺明王将(30)＝棋王＝に99手で勝ち, 対戦成績を4勝3敗として初めて王将位を奪取した。[Challenger Goda 9-dan (age 44) defeats defending champion Watanabe (age 30)—also reigning Kioh holder—in 99 moves as sente to win match 4–3 and capture the Osho title for the first time.]
- "Gōda Ōshō, Habu Meijin wo Yaburi Hatsu Bōei Ōshōsen" 郷田王将, 羽生名人を破り初防衛 将棋王将戦 [Goda Osho defeats Habu Meijin to defend title for the first time since becoming Osho]. Asahi Shimbun (in Japanese). March 19, 2016. Retrieved March 27, 2016.
- Murase, Shinya (March 15, 2017). "Kubo Kudan, Ōshō no Taitoru Dasshu Gōda Ōshō ni Yonshō Nihai" 久保九段, 王将のタイトル奪取 郷田王将に4勝2敗 [Kubo 9-dan defeats Goda Osho 4-2 to capture Osho Title]. Asahi Shimbun (in Japanese). Retrieved March 16, 2017.
- "Kubo Ōshō ga Bōei Shōgi, Toyoshima Hachidan wo Yaburu" 久保王将が防衛 将棋, 豊島八段を破る [Kubo Ōshō defends title, defeats Toyoshima 8d]. The Nikkei (in Japanese). Kyodo News. March 15, 2018. Retrieved March 16, 2018.
- "Eisei Shōgō - Meiyo Shōgō Kakutokusha Ichiran"
[List of Lifetime Title Holders] (in Japanese). Japan Shogi Association. Retrieved March 31, 2015.
王将戦 永世王将 通算10期 大山康晴 (1973)・羽生善治 (2007). [Osho Match: Lifetime Osho, A total of 10 times, Yasuharu Oyama (1973) - Yoshiharu Habu (2007)]