1931 in Japan

Events in the year 1931 in Japan.

Incumbents

 * Emperor: Hirohito
 * Prime Minister:
 * Osachi Hamaguchi: until April 14
 * Wakatsuki Reijirō: April 14 – December 13
 * Inukai Tsuyoshi: from December 13

Governors

 * Aichi Prefecture:
 * starting 20 January: Masao Oka
 * 20 January-21 December: Kosaka Masayasu
 * until 21 December: Yujiro Osaki
 * Akita Prefecture: Koki Hiegata (until 18 December); Takeshi Uchida (starting 18 December)
 * Aomori Prefecture: Migaku Moriya (until 18 December); Teizaburo Miyamoto (starting 18 December)
 * Ehime Prefecture: Koichiro Sasai (until 18 December); Kume Shigeo (starting 18 December)
 * Fukui Prefecture: Tachibana Saitanao (until 18 December); Keizo Ichimura (starting 18 December)
 * Fukushima Prefecture:
 * until 15 April: Koyanagi Makimamoru
 * 15 April-18 December: Goro Kawasaki
 * starting 18 December: Murai Hachiro
 * Gifu Prefecture:
 * until 8 May: Ken Usawa
 * 8 May-18 December: Yoshida Katsutaro
 * starting 18 December: Takehiko Ito
 * Gunma Prefecture:
 * until 27 June: Hotta Kanae
 * 27 June-18 December: Kiichi Harata
 * starting 18 December: Masao Kanazawa
 * Hiroshima Prefecture:
 * until 8 May: Hiroshi Kawabuchi
 * 8 May-18 December: Takekai Shirane
 * starting 18 December: Ryo Chiba
 * Ibaraki Prefecture:
 * until 27 June: Shozo Ushijima
 * 27 June-18 December: Tanaka
 * starting 18 December: Seikichi Kimishima
 * Ishikawa Prefecture: Nakano Kunikazu (until month unknown)
 * Iwate Prefecture: Toyoshiro Kubo (until 18 December); Hidehiko Ishiguro (starting 18 December)
 * Kagawa Prefecture:
 * until 27 June: Susumu Tsuboi
 * 27 June-18 December: Yusai Takahashi
 * starting 18 December: Akira Ito
 * Kanagawa Prefecture: Jiro Yamagata (until month unknown)
 * Kochi Prefecture:
 * until 27 June: Tanaka
 * 27 June-18 December: Tsuboi
 * starting 18 December: Kodora Akamatsu
 * Kumamoto Prefecture: Bunpei Motoyama (until 18 December); Kenichi Yamashita (starting 18 December)
 * Kyoto Prefecture:
 * until October: Sasaki Shinichi
 * October-December: Shinya Kurosaki
 * starting December: Sukenari Yokoyama
 * Mie Prefecture: Keizo Ichimura (until 18 December); Hirose Hisatada (starting 18 December)
 * Miyagi Prefecture: Michio Yuzawa
 * Miyazaki Prefecture:
 * until 18 December: Ariyoshi
 * 18 December-21 December: Kiyoshi Nakarai
 * starting 21 December: Gisuke Kinoshita
 * Nagano Prefecture: Shintaro Suzuki (until 18 December); Ishigaki Kuraji (starting 18 December)
 * Niigata Prefecture:
 * until 2 October: Toyoji Obata
 * 2 October-18 December: Nakano Kunikazu
 * starting 18 December: Obata Toyoji
 * Okinawa Prefecture: Jiro Ino
 * Osaka Prefecture: Saito Munenori (starting month unknown)
 * Saga Prefecture:
 * until 18 December: Inoue
 * 20 January-18 December: Nakarai Kiyoshi
 * starting 18 December: Saburo Hayakawa
 * Saitama Prefecture:
 * until 15 April: Niwa Shichiro
 * 15 April-18 December: Kozo Yamanaka
 * starting 18 December: Umekichi Miyawaki
 * Shiname Prefecture:
 * until 21 August: Keiichi Omori
 * 21 August-18 December: Kanichi Misawa
 * starting 18 December: Rinsaku Yagi
 * Tochigi Prefecture:
 * until 27 January: Harada
 * 20 January-27 December: Asari Saburo
 * starting 27 December: Chokichi Toshima
 * Tokyo: Torataro Shizuka (until 18 October); Hasegawa Hisakazu (starting 18 October)
 * Toyama Prefecture: Kozo Yamanaka (until 15 April); Keiichi Suzuki (starting 15 April)
 * Yamagata Prefecture:
 * until 24 October: Kubota Osamu Kosuke
 * 24 October-18 December: Ken Yamaguchi
 * starting 18 December: Sada Kawamura

Events

 * March - March Incident
 * March 27 – A real estate brand, Shōei Corporation was founded, as predecessor for Hullic.
 * June 5 – 1931 Empress of Canada stabbings: A man killed 2 and wounded 29 others with a knife aboard the Canadian Pacific Steamships liner RMS Empress of Canada as the ship sailed off Japan.
 * June 27 - Nakamura Incident
 * July 1 - Wanpaoshan Incident
 * September 21 – A Richer Scale magnitude 6.5 earthquake hit in Yorii, Saitama Prefecture. According to Japanese government official confirmed report, killing 16 persons, 146 persons were wounded.
 * October 21 - October Incident
 * November 4 - Resistance at Nenjiang Bridge
 * November 4–18 - Jiangqiao Campaign
 * Unknown date
 * Teikyo Commerce School, later Teikyo University was founded in Tokyo.
 * A time recorder and robot brand, Amano was founded in Yokohama, as predecessor name of Amano Manufacturing.
 * A mail order cram school, Jitsuryoku-Zōshinsha (Ability Promotion), as predecessor of Zōshinsha Holdings (Z-kai) was founded.

Films

 * Tokyo Chorus

January–March

 * January 2 – Toshiki Kaifu, Prime Minister of Japan (d. 2022)
 * January 6 – Kaoru Yachigusa, actress (d. 2019)
 * January 20 – Ariyoshi Sawako, writer (d. 1984)
 * January 21 – Yoshiko Kuga, actress (d. 2024)
 * January 28 – Sakyo Komatsu, science fiction writer (d. 2011)
 * February 16 – Ken Takakura, actor (d. 2014)
 * March 7 – Atsuko, Princess Yori, fourth daughter of Emperor Shōwa
 * March 9 – Masahiro Shinoda, film director

April–June

 * April 11 – Koichi Sugiyama, composer and conductor (d. 2021)
 * May 10 – Ichirō Nagai, voice actor (d. 2014)
 * June 22 – Teruyuki Okazaki, black belt in Shotokan Karate (d. 2020)

July–September

 * July 5 – Ryuzo Sato, economist
 * July 11 – Yasuo Ōtsuka, animator (d. 2021)
 * August 29 – Ichikawa Raizō VIII, actor (d. 1969)
 * August 30 – Jōji Yanami, voice actor
 * September 17 – Ayako Sono, writer (d. 2021)
 * September 21 – Syukuro Manabe, Japanese-American meteorologist and climatologist

October–December

 * October 24 – Ken Utsui, actor (d. 2014)
 * November 29 – Shintaro Katsu, actor (d. 1997)
 * December 5 – Kyōko Kagawa, actress
 * December 11 – Fujiko Yamamoto, actress
 * December 15 – Shuntarō Tanikawa, poet and translator
 * December 19 – Reiko Sato, actress and dancer (d. 1981)
 * December 31 – Sakata Tōjūrō IV, kabuki actor (d. 2020)

Full date unknown

 * Miyozo Yamazaki, amateur archaeologist

Deaths

 * January 27 – Nishinoumi Kajirō II, Sumo wrestler, 25th yokozuna (b. 1880)
 * June 13 – Kitasato Shibasaburō, physician and bacteriologist (b. 1853)
 * June 26 – Yamakawa Kenjirō, physicist, university president (b. 1854)
 * August 2 – Kinue Hitomi, sprinter and long jumper (b. 1907)
 * August 26 – Osachi Hamaguchi, Prime Minister of Japan (b. 1870)
 * September 2 – Ichinohe Hyoe, general (b. 1855)
 * November 11 – Shibusawa Eiichi, industrialist (b. 1840)