North Korea Plans to Adjust Time Zone After Spending Two Years 30 Minutes Behind South Korea

As for why North Korea was 30 minutes behind in the first place, it was apparently a point of nationalistic pride.

from gizmodo http://www.gizmodo.co.uk/2018/04/north-korea-plans-to-adjust-time-zone-after-spending-two-years-30-minutes-behind-south-korea/