Japan PM unveils plan to amend Constitution, put into force in 2020 - The Mainichi

TOKYO (Kyodo) -- Japanese Prime Minister Shinzo Abe on Wednesday unveiled a plan to seek a first-ever change to the postwar Constitution, bidding to see the revision take effect in 2020, a specific time frame not publicly mentioned before.

http://mainichi.jp/english/articles/20170503/p2g/00m/0dm/075000c