Mukai Chiaki
Mukai Chiaki (向井千瑛, born 24 December 1987) is a Nihon Ki-in professional. (She reached 1 dan in 2004, 2 dan in 2007, 3 dan in 2009, 4 dan in 2010, 5 dan on 2012-02-01, 6 dan from 20 February 2021 (with 90 wins) and is a disciple of Honda Sachiko.
According to the Rating list, 2024-01-02, Mukai Chiaki is the #46 ranked female and #500 overall in the world, and #8 female in Japan.
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Name and Family
Her surname Mukai 向井 means “Towards the well (i.e. water well)”, from 向 (Mu) = towards, direction, facing; and 井 (Kai) meaning well or spring. The characters in Chinese have the same meaning, but are pronounced Xiàngjǐng or Xiàngjǐ.
Her given name Chiaki 千瑛 means “A thousand gems”, from 千 (Chi) = thousand and 瑛 (Aki or E) = gem. In Chinese it would have the same meaning but be pronounced Qiānyīng or Qiānchēng. The characters for Chiaki 千瑛 can also be read Chie. However, her fellow female professional Kato Chie's given name has a different second character, 千笑, and means “A thousand smiles”. (Another Mukai Chiaki (向井 千秋, b. 6 May 1952), with a different second character of her given name, was the first Japanese and indeed Asian woman in space and a cardiovascular surgeon.)
Mukai Chiaki’s two older sisters Nagashima Kozue and Mimura Kaori are also professionals and fellow pupils of Honda Sachiko (herself one of three professional Go-playing sisters).
Mukai Chiaki married Sugimoto Akira 8p, 14 years older, in September 2013. They have one son, Kazuki, born in May 2014. Mukai Chiaki is the only one of the three sisters not to have taken her husband's name after marriage.
The four Kobayashi siblings (Kobayashi Chizu, Kobayashi Satoru, Kobayashi Kenji, and Kobayashi Takayuki, are her first cousins once removed (her mother's cousins; Kobayashis’ father and Mukai's maternal grandfather were brothers).
Winner and runner-up
- Challenger for the 11th Female Kisei in 2008 (lost to Umezawa Yukari)
- Challenger for the 22nd Female Meijin hold by Xie Yimin in 2010 (after winning the league 5–1)
- Challenger for the 29th Female Honinbo hold by Xie Yimin in 2010, defeating Umezawa Yukari in the challenger final. Xie Yimin won the match for the title 3–0.
- Challenger for the 23rd Female Meijin hold by Xie Yimin in 2011. Lost the match 1–2.
- Challenger for the 30th Female Honinbo hold by Xie Yimin in 2011. Lost the match 1–3.
- Challenger for the 24th Female Meijin hold by Xie Yimin in 2012. Lost the match 0–2.
- Winner in 2013 of the 32nd Female Honinbo. Beat defending champion Xie Yimin 3–2.
- Runner+up in 2014 of the 33rd Female Honinbo. Lost her title to challenger Fujisawa Rina 0–3.
- Runner up in the 2016 Female Strongest.
- Challenger to the 2024 Tachiaoi Cup, facing defending champion Ueno Asami. Lost the match 0–2.
- Challenger to the 2025 Female Kisei, beating the two top rated Japanese females Fujisawa Rina and Ueno Asami on the way. Now facing defending champion Ueno Risa (currently behind 0–1).
Head-to-head scores against current female rivals
(Based on Mukai Chiaki, rating and game list, 20 Dec 2025)
- Mimura Kaori, 3p, her oldest sister: 0–1
- Nagashima Kozue, 3p, her older sister: 1–0
- Fujisawa Rina, 7p, #6 female in world, #2 female in Japan: 3–9
- Xie Yimin, 7p, former #1 female in Japan: 12–21
- Ueno Asami, 6p, #3 female in the world, #1 female in Japan: 1–9
- Nakamura Sumire, 3p, girl prodigy, #14 ranked female and #3 female teenager in the world, #3 ranked female in Japan, once Female Kisei: 1–2
- Ueno Risa, 3p, Asami’s younger sister, #22 female and #4 female teenager in world, #4 female in Japan, Female Kisei: 1–4
- Aoki Kikuyo, 8p, 5× Women's Meijin, 4× Women's Kakusei, once Female Kisei: 3–3
- Yoshida Mika, 8p, 4× Women's Honinbo, 4× Kansai Ladies' Tournament, once Women's Kakusei: 7–1
- Chinen Kaori, 6p, 5× Female Kisei, 4× Women's Honinbo: 4–3
- Kobayashi Izumi, 7p, 3× Female Honinbo], 3× Female Meijin, 2× Female Kisei, once Teikei Cup Female Legends: 3–2
- Kato Keiko, 6p, once Women's Meijin, once Female Strongest: 9–7
- Yashiro Kumiko, 6p, 2× Women's Honinbo, 3–1
- Umezawa Yukari, 6p, 3× Female Kisei: 3–4
- Suzuki Ayumi, 7p, #7 female in Japan, #33 female in world, twice Female Strongest, once Female Kisei: 6–11
- Koyama Terumi, 6p, 4× Women's Meijin: 6–0
- Nyu Eiko, 4p, 2× Female Strongest: 4–1
- Konishi Kazuko, 8p, once Kansai Ladies' Tournament, once Teikei Cup Female Legends: 1–0
- Mannami Kana, 4p, 2× Female Kisei: 0–1
- Mannami Nao, 4p, Kana’s younger sister, once Female Strongest: 4–3
- Hoshiai Shiho, 4p, once Female Honinbo challenger: 4–1
- Joanne Missingham, 7p, aka Hei Jiajia, #1 female in Taiwan, #39 female in world: 0–2
- Rui Naiwei, 9p, long-time world female #1: 0–2
- Choi Jeong, 9p, current Korean and World #1 female: 2–3
- Yu Zhiying, 6p, current China #1 and World #2 female: 1–5
- Lu Minquan, 6p, #6 female in world, #3 female in China: 1–0
- Song Ronghui, 5p, #49 female in world: 1–1
- Li He, 5p, #10 female in world, #4 female in China: 0–2
- Cho Hyeyeon, 9p, once World #1 and often World #2 behind Rui Naiwei: 2–0
- Kim Chaeyeong, 9p, #8 female in world, #4 female in South Korea, 2× Women's Kuksu, 1–0
- Kim Dayoung, 5p, Kim Chaeyeong’s younger sister, #27 ranked female in the world and #9 female in Korea: 0–0
- Wang Chenxing, 5p, #16 female in world, #8 female in China: 2–2
- Kim Hye-min, 9p, #25 female in the world, #8 female player in Korea: 1–1
- O Jeonga, 5p: 0–1
Career record
Mukai has played almost 800 professional games and won well over half of them. Her overall professional game record is 799 games, 450 wins, and 349 losses, for a 56.3% win rate. For a few years after the birth of her son in 2014, she played far fewer games and and with less success.
After her son was in school, she could play more games, and achieve greater success. In 2024, she reached two finals, the 2024 Tachiaoi Cup and 2025 Female Kisei. In the latter, she beat the leading title winners Xie Yimin 27, Fujisawa Rina 26, and Ueno Asami 15.
It was the first time she had beaten Ueno Asami after 9 losses. Her husband encouraged her, “change your mindset and fight”, and she said, “I was going to win against my fear.” She took the initiative in the middlegame and widened her lead enough to win (B+5.5). She wrily said after the game, “I’m sorry. I prevented the sister showdown,” i.e. between Ueno Asami and Ueno Risa. But Mukai’s challenge was unsuccessful, losing 0–2 to the title holder Ueno Risa.
The Go to Everyone and Go Ratings sites conflict in the numbers.
Year | total | wins | losses | rate |
---|---|---|---|---|
2004 | 12 | 4 | 8 | 33% |
2005 | 20 | 10 | 10 | 50% |
2006 | 42 | 27 | 15 | 64% |
2007 | 35 | 20 | 15 | 57% |
2008 | 44 | 26 | 18 | 59% |
2009 | 35 | 22 | 13 | 63% |
2010 | 36 | 19 | 17 | 53% |
2011 | 51 | 28 | 23 | 55% |
2012 | 37 | 17 | 20 | 47% |
2013 | 42 | 22 | 20 | 52% |
2014 | 21 | 6 | 15 | 28.6% |
2015 | 9 | 2 | 7 | 22.2% |
2016 | 11 | 6 | 5 | 54.5 |
2017 | 51 | 32 | 19 | 63% |
2018 | 7 | 3 | 4 | 42.9% |
2019 | 13 | 7 | 6 | 53.8% |
2020 | 50 | 24 | 13 | 65% |
2021 | 18 | 6 | 33% | |
2022 | 49 | 30 | 19 | 61% |
2023 | 42 | 27 | 15 | 64% |
2024 | 44 | 29 | 15 | 66% |
Outside links
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Nikon Ki-in player profile
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Japanese Wikipedia
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IgoDB
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Japanese Go blog of all three Mukai sisters
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Go Ratings and Games
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Go4Go
Pictures

Mukai Chiaki with baby son Kazuki, 2014 (Image credit: pandanet.co.jp

Mukai Chiaki with husband Sugimoto Akira and their baby son Kazuki, 2014, (Image credit: pandanet.co.jp
Ueno Asami selfie with (L→R) Mukai Chiaki, Ueno Risa, Nakamura Sumire, and Fujisawa Rina, Tachioi Cup, 2023 (Image credit: nikkansports.com