January 1 – A strong (magnitude 7.0), but very deep (370 km) earthquake shakes large parts of Eastern Japan at a JMA-intensity of 4. The quake with an epicenter about 500 km South of mainland Tokyo in the Pacific Ocean near Torishima, Tokyo doesn't cause any reported serious damage or injuries, but can be felt (intensity≥1) from Southern Hokkaidō to Chūgoku.[3][4]
January 13 – In a cabinet reshuffle, Prime Minister Noda replaces five ministers, including two who had been the subject of censure motions by the opposition dominated upper house in December 2011; Katsuya Okada becomes deputy prime minister.[6][7]
late January and early February – At least 50 people die in heavy snow and record low temperatures across the country.[8][9]
February 5 – Kyoto City mayoral election: In the traditional Communist stronghold, incumbent mayor Daisaku Kadokawa won re-election with support from the major parties against Japanese Communist Party-supported Kazuo Nakamura by 54 to 46 percent of the vote.
March 31 – Analogue television broadcasts are terminated in the prefectures of Miyagi, Fukushima and Iwate as Japan completed its digital switchover since it was started last July 24, 2011.
April 12 – A car in Higashiyama-ku, Kyoto crashed into a pole and hit multiple pedestrians, resulting in eight dead (including the driver) and twelve injured. The accident, which was later attributed to the driver's epilepsy, was the worst traffic accident in Japan since 1996.[17]
May 22 – Tokyo Skytree, which was completed on 29 February 2012, officially opened to the public.
June 5 – In a cabinet reshuffle, prime minister Noda replaces five ministers, including two who had been subject to censure by the opposition dominated upper house in April 2012; Satoshi Morimoto becomes the first non-parliamentarian defence minister.[19]
September 22 – [28] Party president Natsuo Yamaguchi of Kōmeitō is re-elected unchallenged as no other candidate has filed a candidacy before the official campaign start on September 14.[29]
October 1 – Prime minister Yoshihiko Noda reshuffles his cabinet for the third time;[30] newly appointed justice minister Keishū Tanaka soon faces calls to resign over a report about an (illegal) political donation from a foreigner and contacts to Yakuza members.[31]
October 21 – Niigata governor Hirohiko Izumida, supported by the major non-communist parties (DPJ, LDP, LF, Kōmeitō, SDP),[32] is reelected for a third term against Communist challenger Shijio Hiwatashi and perennial Smile Party candidate Mac Akasaka.[33]
October 28 – Gubernatorial elections in Okayama and Toyama and by-election for the House of Representatives in Kagoshima 3rd district: In Toyama, incumbent Takakazu Ishii is reelected for a third term; in Okayama, former Tenmaya department store president Ryūta Ibaragi succeeds retiring Masahiro Ishii; Kazuaki Miyaji wins the by-election to replace Tadahiro Matsushita, further reducing prime minister Noda's coalition majority after a string of defections.[34][35]
November 18 – In the Tochigi gubernatorial election, incumbent Tomikazu Fukuda is reelected for a third term.[36]
