[1] He obtained professional status and the rank of 4-dan on April 1, 2007, after finishing tied for first with Kōta Kanai in the 40th 3-dan League (October 2006 – March 2007) with a record of 14 wins and 4 losses.
[2] Toyoshima, together with Akira Inaba, Tetsurō Itodani and Akihiro Murata, is one of four Kansai-based young shogi professionals who are collectively referred to as the Big Young Kansai Four (関西若手四天王, Kansai Wakate Shitennō).
[3] Toyoshima's first appearance in a major title match came in 2010 when he defeated Yasumitsu Satō to win the 60th Ōshō league with a record of 5 wins and 1 loss, Although Toyoshima lost his first game in league play, he proceeded to win his next five to earn the right to challenge defending Ōshō Toshiaki Kubo for his title.
[7] In July 2014, Toyoshima defeated Tadahisa Maruyama to win the right to challenge Yoshiharu Habu for the 62nd Ōza title.
[15] Two days after his loss to Yamazaki, Toyoshima defeated Kōichi Fukaura on November 21, 2017, to win the 67th Ōshō league with a record of 5 wins and 1 loss and earn the right to challenge Kubo once again for the Ōshō title.
[17] On July 17, 2018, Toyoshima defeated Habu in Game 5 of the 89th Kisei match to capture his first major title.
Toyoshima won the match 2 games to 1 and became a challenger for the Ryūō title for the first time.
Fujii won the match 4 games to none to drop Toyoshima from the ranks of current major title holders.
[35][36] Toyoshima and Fujii met about a week after the conclusion of the 34th Ryūō in the championship game of the 42nd Nihon Series JT Professional Tournament: Toyoshima defeated Fujii to repeat as champion and win the tournament for the third time overall.
[37] Toyoshima defeated Ayumu Matsuo in March 2022 to win the 71st NHK Cup.
[46] Toyoshima has received a number awards and honors throughout his career for his accomplishments both on an off the shogi board.