Toshiaki Kubo

Kubo's first major title victory came in 2009 when he defeated Yasumitsu Satō 3 games to 2 to take the 34th Kiō title. Kubo successfully defended his title for the next two years by defeating Satō once again 3 games to 2 in 2010 and Akira Watanabe 3 games to 1 in 2011. Kubo, however, was unable to defend his title for the third consecutive year, losing the 37th title match to Gōda 3 games to 1.

In 2008, Kubo challenged Habu for the 57th Ōshō title, but lost the match 4 games to 1. The two met again in 2009 for the 59th Ōshō title, and this time Kubo was the winner by the score of 4 games to 2. The victory made Kubo a "2-crown" (a player who simultaneously holds two major titles) for the first time. Kubo successfully defended his title the following year by defeating Masayuki Toyoshima 4 games to 2, but lost the 61st Ōshō title match to Satō 4 games to 1 in 2012. Kubo won the title for the third time in 2017 when he defeated Gōda 4 games to 2 to win the 66th Ōshō title, and successfully defend his title in 2018 when defeated Toyoshima once again 4 games to 2 to win the 67th Ōshō title. Kubo, however, was unable to defend his title once again the following year when he lost the 68th Ōshō match to Watanabe 4 games to none.

Kubo's first appearance in a major title match came in 2000 when he challenged Yoshiharu Habu for the 26th Kiō title. Kubo advanced to the title match by defeating Masataka Gōda 2 games to 0 to win the two-game challenger playoff, but was unable to defeat Habu, losing the match 3 game to 1. The following year, he also challenged Habu for the 49th Ōza title, but lost once again by the same score. In 2007, Kubo once again challenged Habu in the 55th Ōza title match, but was defeated 3 games to 0.

Toshiaki Kubo (久保 利明 , Kubo Toshiaki, born August 27, 1975) is a Japanese professional shogi player ranked 9-dan. He is a former Ōshō and Kiō title holder.　

Kubo was born in Kakogawa, Hyōgo on August 27, 1975. He learned shogi when he was about four years old, and at the encouragement of a friend of his father soon began playing regularly at the Kobe Shogi Center in neighboring Kobe. The center was managed by shogi professional Hitoshige Awaji [ja] who became Kubo's shogi teacher after the two played a 19-piece "Naked King" handicap game. In 1986, he advanced to the semi-finals of the 11th Elementary Student Meijin Tournament [ja] as fifth-grade elementary school student, but lost to the eventual tournament winner and fellow future shogi professional Daisuke Suzuki. Later that same year, Kubo entered the Japan Shogi Association's apprentice school at the rank of 6-kyū under the guidance of Awaji. He was awarded professional status and the rank of 4-dan on April 1, 1993, at the age of 17.