Toshihide Maskawa
益川 敏英
Maskawa in 2008
Born(1940-02-07)7 February 1940
Died23 July 2021(2021-07-23) (aged 81)
Alma materNagoya University
Known forWork on CP violation
CKM matrix
SpouseAkiko Takahashi
AwardsSakurai Prize (1985)
Japan Academy Prize (1985)
Asahi Prize (1994)
Nobel Prize in Physics (2008)
Scientific career
FieldsHigh energy physics (theory)
InstitutionsNagoya University
Kyoto University
Kyoto Sangyo University
Thesis粒子と共鳴準位の混合効果について. (1967)
Doctoral advisorShoichi Sakata

Toshihide Maskawa (or Masukawa) (益川 敏英, Masukawa Toshihide, 7 February 1940 – 23 July 2021) was a Japanese theoretical physicist known for his work on CP-violation who was awarded one quarter of the 2008 Nobel Prize in Physics "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature."[1]

Early life and education

Maskawa was born in Nagoya, Japan. After World War II ended, the Maskawa family operated as a sugar wholesaler. A native of Aichi Prefecture, Toshihide Maskawa graduated from Nagoya University in 1962 and received a Ph.D. degree in particle physics from the same university in 1967. His doctoral advisor was the physicist Shoichi Sakata.[2][3][4]

From early life Maskawa liked trivia, also studied mathematics, chemistry, linguistics and various books. In high school, he loved novels, especially detective and mystery stories and novels by Ryūnosuke Akutagawa.[2]


At Kyoto University in the early 1970s, he collaborated with Makoto Kobayashi on explaining broken symmetry (the CP violation) within the Standard Model of particle physics. Maskawa and Kobayashi's theory required that there be at least three generations of quarks, a prediction that was confirmed experimentally four years later by the discovery of the bottom quark.

Maskawa and Kobayashi's 1973 article, "CP Violation in the Renormalizable Theory of Weak Interaction",[5] is the fourth most cited high energy physics paper of all time as of 2010.[6] The Cabibbo–Kobayashi–Maskawa matrix, which defines the mixing parameters between quarks was the result of this work. Kobayashi and Maskawa were jointly awarded half of the 2008 Nobel Prize in Physics for this work, with the other half going to Yoichiro Nambu.[1]

Maskawa was director of the Yukawa Institute for Theoretical Physics from 1997 to 2003.[7] He was special professor and director general of Kobayashi-Maskawa Institute for the Origin of Particles and the Universe at Nagoya University,[8] director of Maskawa Institute for Science and Culture at Kyoto Sangyo University[9] and professor emeritus at Kyoto University.

Nobel lecture

On 8 December 2008, after Maskawa told the audience "Sorry, I cannot speak English", he delivered his Nobel lecture on “What Did CP Violation Tell Us?” in Japanese language, at Stockholm University. The audience followed the subtitles on the screen behind him.[10]

Personal life

Maskawa married Akiko Takahashi in 1967. The couple have two children, Kazuki and Tokifuji.


On 23 July 2021 at the same day as the opening ceremony of Tokyo Summer Olympic Games, Maskawa died of oral cancer at his home in Kyoto at the age of 81.[11][12] Although his death was unrelated to triple disaster and COVID-19 infection. He was cremated in October 2021 after the private funeral.

Professional record


Paul Krugman, Roger Tsien, Martin Chalfie, Osamu Shimomura, Makoto Kobayashi and Toshihide Masukawa, Nobel Prize Laureates 2008, at a press conference at the Swedish Academy of Science in Stockholm

Political proposition

Maskawa's slide rule on display at the Nobel Prize Museum

In 2013, Maskawa and chemistry Nobel laureate Hideki Shirakawa issued a statement against the Japanese State Secrecy Law.[13]" The following is Maskawa's main political proposition:

See also


  1. ^ a b "The Nobel Prize in Physics 2008". The Nobel Foundation. Retrieved 17 October 2009.
  2. ^ a b "Toshihide Maskawa - Biographical".
  3. ^ "Nagoya University World Class Researchers". Nagoya University.
  4. ^ "Toshihide Maskawa". Kyoto University.
  5. ^ M. Kobayashi, T. Maskawa (1973). "CP-Violation in the Renormalizable Theory of Weak Interaction". Progress of Theoretical Physics. 49 (2): 652–657. Bibcode:1973PThPh..49..652K. doi:10.1143/PTP.49.652. hdl:2433/66179.
  6. ^ "Top Cited Articles of All Time (2010 edition)". SLAC. 2009. Retrieved 21 June 2014.
  7. ^ "History of YITP". Yukawa Institute for Theoretical Physics. 23 February 2017.
  8. ^ "Message from Director | Nagoya University: Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI)". Archived from the original on 22 July 2011. Retrieved 12 January 2022.
  9. ^ [1][permanent dead link]
  10. ^ Toshihide Maskawa - Nobel Lecture: What Does CP Violation Tell Us?
  11. ^ McClain, Dylan Loeb (10 August 2021). "Toshihide Maskawa, a Nobel Prize-Winning Physicist, Who Helped Unlock a Cosmic Mystery, Dies of Oral Cancer at 81". The New York Times.
  12. ^ ノーベル物理学賞受賞 益川敏英さん死去 81歳 (in Japanese)
  13. ^ Updated: Over Scientists' Objections, Japan Adopts State Secrets Law | Science | AAAS
  14. ^ 「九条科学者の会」呼びかけ人メッセージ (2005.3.13)
  15. ^ "益川敏英博士「日本の平和憲法は改悪の危機」". 朝鮮日報/朝鮮日報日本語版 (2013/07/14 01:31)。