Kim Il-Sung
In 1997 with Kim Jong Il fully consolidating his power after the death of his father, North Korea abandoned the Gregorian calendar that is used in the rest of the world. Instead they use the Juche calendar which starts from the year of Kim Il Sung's birth (1912) as being year 1. For example, 2015 would be written as Juche 104. To calculate the date in Juche years, simply subtract 1911 from the current year. Dates are often written in North Korea with Juche first; for example: April 12, Juche 104 (2015).