1923 in Japan

Incumbents

• Emperor: Taishō
• Regent: Hirohito
• Prime Minister:
• *Katō Tomosaburō
• *Yamamoto Gonnohyōe

  Events

• April unknown date - Yamanouchi Pharmaceutical was founded, as predecessor part of Astellas Pharma.
• May - 1923 Far Eastern Games held in Osaka.
• August 24 - Prime Minister Katō Tomosaburō dies in office.
• August 29 - Fuji Electric Manufacturing, later Fuji Electric was founded.
• September 1 - The Great Kantō earthquake devastates Tokyo and Yokohama, killing an estimated 142,807 people, but according to a Japanese construction research center report in 2005, 105,000 are confirmed dead. Varied accounts indicate the duration of the earthquake was between four and ten minutes.
• September 1-21 - Kantō Massacre: Young Japanese vigilante groups, driven by rumors of a Korean revolt, attack and murder thousands of Korean residents.
• September 2
• *Yamamoto Gonnohyōe is appointed Prime Minister of Japan.
• *Martial law declared in Tokyo districts
• September 3-5 - Kameido incident
• September 4 - The area of martial law is expanded to cover all of Tokyo, Kanagawa, Chiba, and Saitama prefectures.
• September 7 - A Curfew is issued in Tokyo.
• September 16 - Amakasu Incident: The feminist Noe Itō and her partner, the anarchist Sakae Ōsugi are beaten and killed by a police squadron led by Lieutenant Amakasu Masahiko, along with Ōsugi's six-year-old nephew, and their bodies disposed in a well. Following countrywide outcry, Amakasu was court-martialed and sentenced to 10 years in prison.
• December 27 - Toranomon Incident: An assassination attempt is made on the crown prince Hirohito in Tokyo by Daisuke Namba, but the attempt fails.
• Unknown date -Yamanouchi Pharmacy, as predecessor of Astellas was founded.

  Births

• March 27 - Shūsaku Endō, writer
• May 24 - Seijun Suzuki, filmmaker, actor, and screenwriter
• June 4 - Yuriko, Princess Mikasa, wife of Prince Takahito
• August 7 - Ryōtarō Shiba, writer
• October 7 - Tomio Aoki, film actor

  Deaths

• January 8 - Shimamura Hayao, Marine Admiral
• February 3 - Kuroki Tamemoto general
• February 4 - Prince Fushimi Sadanaru, Field Marshal
• April 1 - Prince Naruhisa Kitashirakawa, military personnel
• June 9
• *Takeo Arishima, novelist, writer and essayist
• *Akiko Hatano, journalist
• June 19 - Shō Shō, member of the House of Peers
• August 24 - Katō Tomosaburō, Prime Minister of Japan
• September 1 - Matsuoka Yasukowa, politician and cabinet minister
• September 2 - Kuriyagawa Hakuson, literary critic
• September 16
• *Noe Itō, anarchist, social critic and author
• *Sakae Ōsugi, anarchist
• November 8 - Fusakichi Omori, seismologist
• November 26 - Otani Kikuzo, general
• December 29 - Kōno Hironaka, politician