(born June 24, 1969, in Wakkanai, Hokkaido) is a Japanese women's professional shogi player ranked 6-dan. She is a former women's shogi professional major title holder, having won 19 major titles throughout her career, and has been awarded the lifetime title of Queen Meijin, and also was the first women's professional to beat a regular shogi professional in an official game, the first women's professional to win an official game against a Class A professional, and the first women's professional to win a game in the NHK Cup TV Shogi Tournament.
Nakai also is a former representative director of the Ladies Professional Shogi-player's Association of Japan (LPSA).
Nakai started playing shogi at the age of 4. She finished second in the in 1981 at the age of 11. In 1983, she entered the Japan Shogi Association's apprentice school and reached the rank of 2-kyà « before deciding to leave in 1990.
Nakai was awarded the rank of women's professional 2-kyà « by the Japan Shogi Association in April 1981 at the age of 11 as a protegee of .
In 1993, Nakai became the first women's professional to defeat a regular professional in an official game when she beat in a Ryà «à  tournament game.
Nakai was 16 years old when she won her first major title in 1985 by defeating the reigning Women's Meijin Naoko Hayashiba three games to one to win the Women's Meijin title. The following year the roles were reversed with Nakai successfully defending her title against the challenger Kobayashi three games to two.
In 2003, Nakai became the first women's professional to win a NHK Cup TV Shogi Tournament game. She won her round 1 game of the 53rd NHK Cup (2003) against Mamoru Hatakeyama and then in round 2 won against Teruichi Aono (who was in Class A at the time). She lost in round 3 to Makoto Nakahara. The following year Nakai also qualified for the 54th NHK Cup (2004) and beat Shà «ji Satà  in round 1. In round 2, Nakai faced Yasumitsu Satà  who was the reigning Kisei title holder. Nakai obtained an advantageous position against Satà Â, but was unable to convert it into a win. Nakai is still the only women's professional to have won a NHK Cup game.
In April 2009, Nakai became the first women's professional to win 500 official games, and then became the first women's professional to win 600 official games in January 2015.
In August 2010, Nakai defeated Sayuri Honda in the quarterfinals of the to win her nineteenth official game in a row and set a new record for consecutive wins by a women's professional.
In October 2020, Nakai at 51 years and 3 months old became the oldest challenger for a women's major title when she defeated Sakura Ishimoto in the finals of the challenger tournament for the 28th Kurashiki TÃ Âka Cup. The win advanced Nakai to a women's major title match for the first time in 16 years and it also broke the previous record for oldest title challenger of 49 years and 8 months set two years earlier by Ichiyo Shimizu. Nakai's challenge, however, was unsuccessful as she lost the 48th Kurashiki TÃ Âka Cup title match against Kana Satomi 2 games to none.
Nakai has been promoted as follows.
Note: All ranks are women's professional ranks.
Nakai has appeared in major title matches a total of 44 times and has won a total of 19 titles. She has won the Women's Meijin title nine times and has been awarded the title of Queen Meijin. She has also won the title four times, the title three times and the Kurashiki TÃ Âka Cup three times. In addition to major titles, Nakai has won 17 other shogi championships.
Note: Tournaments marked with an asterisk (*) are no longer held or currently suspended.
Nakai received a number of Japan Shogi Association Annual Shogi Awards and other awards in recognition of her accomplishments in shogi and contributions made to Japanese society.
Nakai was selected to be the first representative director of The Ladies Professional Shogi-player's Association of Japan (LPSA) after it was established in 2007, and served in that capacity until 2010.
Nakai is married to retired shogi professional . The couple have three daughters. She served as a member of the Warabi, Saitama board of education from 2003 to 2015 and was named a "Warabi City PR Ambassador" in May 2016.