Pyongyang: North Korea has decided to switch to a new time zone from August 15, 30 minutes away from the same time zone as Japan and South Korea, state news agency Korean Central News Agency said.
August 15 is the day when Korea liberated itself from Japanese occupated at the end of World War 2.
North Korea is presently in the same time zone as South Korea and Japan, which is nine hours ahead of GMT.
From August 15, North Korea will put its clocks back by 30 minutes.
A KCNA report said: The "wicked Japanese imperialists" had "deprived Korea of even its standard time" by changing the clocks during occupation.
The entire Korean peninsula - then one country - was eight and a half kours ahead of GMT until Japan occupied it in 1910.
KCNA said, the decision reflects "the unshakeable faith and will of the service personnel and people on the 70th anniversary of Korea's liberation".