1) October observance 2) Public holiday in South Korea
Found on
https://www.crosswordclues.com/clue/gaecheonjeol
==Origin== Gaecheon (or `Opening of Heaven`) refers to 3 October B.C. 2457, the date when Hwanung (환웅) descended from heaven to live with mankind. The harvest ceremony was celebrated in each Korean kingdoms; Yeonggo (영고) of Buyeo, Mucheon (무천) of Yemaek, Gyeeum (계음) of Mahan and Byeonhan, Dongmaeng (동맹) of Goguryeo, Palgwanhe.....
Found on
http://en.wikipedia.org/wiki/Gaecheonjeol
No exact match found.
