2005 in Japan

• January 1: The statute of limitations for murder cases is extended from 15 to 25 years.

• February 17: Chubu Centrair International Airport opens.

• March 2: A Nanpū express train on the Tosa Kuroshio Railway Sukumo Line derails and crashes into Sukumo Station, killing the train driver.
• March 16: The Shimane Prefecture assembly declares "Takeshima Day" to commemorate the centennial anniversary of Japan's claim to Liancourt Rocks (known as Takeshima in Japan, and Dokdo in Korea), starting a wave of protests in South Korea.
• March 20: 2005 Fukuoka earthquake[2]

Expo 2005 in Aichi

• March 25: Expo 2005 opens in Aichi Prefecture. Also that day, Lazytown premieres on TV Asahi, but it was not a success, airing its last on that channel 2 weeks later before Moving to NHK General Television.

• April 1
  • Shizuoka City is designated by government ordinance.
  • The Japan-Mexico free trade agreement becomes effective
  • Tokyo Metropolitan University is established.
• April 20: A magnitude 5.8 earthquake hits Fukuoka Prefecture, injuring 56.
• April 25: 107 commuters are killed, 562 injured in the Amagasaki rail crash near Osaka.

• May 3: A Shizuoka Prefecture police helicopter crashes in Shizuoka city, killing five police officers who were on board.

• June 23
  • 60th anniversary of the Battle of Okinawa - a ceremony to remember the dead is held at the Okinawa Prefectural Peace Park.
  • The first case of the H5N2 virus in Japan is discovered on a chicken farm in Jōsō, Ibaraki.

• July 15: Two tankers collide in the Kumano Sea, with one bursting into flames, resulting in one death.

• August 8: Postal service privatization, the keystone of Prime Minister Koizumi's platform, is voted down in the House of Councillors. Later in the day, Koizumi announces the dissolution of the House of Representatives and snap elections to be held the following month.7
• August 24: The Tsukuba Express line opens.

• September 11: Following a general election, the Liberal Democratic Party wins the largest House of Representatives majority in postwar history, holding a two-thirds supermajority along with coalition partner New Komeito.
• September 17: Seiji Maehara defeats Naoto Kan for the presidency of the Democratic Party of Japan.
• September 21: Koizumi is re-elected as prime minister at an extraordinary session of the Diet.
• September 25: Expo 2005 ends.

• October 1: Mitsubishi UFJ Financial Group is formed by the merger of two Japanese banking conglomerates.
• October 14: The Postal Privatisation Bill enters the Diet.
• October 17: Koizumi visits Yasukuni Shrine for the first time since 2004.
• October 31: Koizumi reshuffles his cabinet, naming Shinzo Abe as Chief Cabinet Secretary, Heizo Takenaka as Minister of Internal Affairs and Taro Aso as Minister of Foreign Affairs.

• November 15: Princess Sayako marries commoner Yoshiki Kuroda, thus giving up her imperial title.
• November 17: Structural Calculation Forgery Problem is discovered, and it becomes a serious social problem.

• December 25: An express train bound for the city of Niigata, Niigata Prefecture derails due to strong winds in Shonai, Yamagata Prefecture, killing 5 and injuring at least 33.

Japanese official abandoned national project and development of superconducting passenger ferry Techno Superliner, due to high fuel cost.