October 3^rd which is called Kaechon Day is the day that Tangun founded Ancient Joson, the first state of our country, and acceded to the throne.

   In old books such as Samguksagi, Jewangungi, Samgukyusa, Kyuwonsahwa, it is recorded that Tangun became the king on October 3, Mujin Year, while in the books like Tankikosa and Sindansilgi, it is written that Tangun was born on October 3, Kapja Year, which was called Kaechon Day, and Tangun became the king on October 3, Mujin Year.

   Kaechon meaning opening the sky also referred to opening a civilized world on the land. Our ancestors have celebrated Kaechon Day every year, regarding the birth of Tangun and the founding of Ancient Joson, as a great auspicious event. After the Tangun Korea, Koguryo used to hold a National Congress in October as a biggest event of the year, while its people made rice-cakes from new crops after harvest in early October to hold memorial services to the spirit of Tangun in the sky.

   In Juche 82(1993), the excavation on the mausoleum of King Tangun was undertaken and his remains and relics were found. These findings were confirmed to date back 5011 years ago, thereby, clarifying that Tangun was a sure founding father of Ancient Joson and of the Korean nation.

   On September 27, Juche 82(1993), President Kim Il Sung visited Kangdong area and chose a place for the mausoleum of King Tangun to be rebuilt on a hill at the foot of Mt. Taebak and laid out a blueprint to rebuild the mausoleum of King Tangun into a mausoleum suited to the founder king. Chairman Kim Jong Il organized the Reconstruction Committee for Mausoleum of King Tangun and gave guidance to rebuild the mausoleum excellently.

   Thanks to the wise leadership of President Kim Il Sung and Chairman Kim Jong Il, the Kaechon Day is commemorated on every 3^rd of October at the Mausoleum of King Tangun which has been excellently rebuilt at the foot of Mt. Taebak in Munhung-ri, Kangdong County, Pyongyang.