The Gaya National Research Institute of Cultural Heritage has disclosed a wooden tablet from the Silla Kingdom, excavated from the Seongsan Fortress in Haman County, South Gyeongsang Province.
 
The institute on Wednesday revealed the tablet, which can shed light on the kingdom's governing and tax system.
 
The tablet, known as mokgan in Korean, is estimated to have been made in the mid-sixth century and carries 56 letters.
 
The research institute said words on the tablet show that the Silla Kingdom had a centralized power system. It is a report bearing an apology from a village official to a central bureaucrat.
 
The institute excavated 23 wooden tablets during its 17th excavation work, which ran from 2014 to 2016. Some 350 tablets have been discovered at the Seongsan Fortress site to date, which is half of all ancient tablets found in South Korea.