An independent candidate running in a regional by-election revealed a photo of what he claims is a centuries-old instruction book for Hangul, deemed missing since 2008.
Bae Ik-gi is running for the National Assembly seat for Sangju, Gunwi, Uiseong and Cheongsong regions in Wednesday's election.
Bae, a self-claimed scholar and collector of old books, released a photo of what he claims is the Sangju edition of the Hunminjeongeum Haerye, an instruction book on Hangul, the Korean alphabet, published in 1446 by King Sejong (1397-1450).
In the photo, the bottom edges of the book are charred, possibly damaged in a fire that broke out in Bae's house in March 2015.
The National Election Commission previously denied Bae's attempts to report the book as his property, stating it "could not confirm (Bae's) possession (of the book)."
"I tried to report the property because I am in possession of the Sangju edition," said Bae.
"If I have to reveal it, now during the re-election is the appropriate time."
Bae was previously imprisoned on the charge of stealing the Sangju edition from an old books seller.
The Supreme Court found him not guilty in May 2014.
Two editions of the Hunminjeongeum Haerye are known to exist: The Gangsong edition, discovered in Andong and currently held by the Gansong Art and Culture Foundation, and the Sangju edition.
Bae came forward as the owner of the Sangju edition in 2008, stating he would hand it over to the government in return for 100 billion won (S$123 million).
Since then, the Sangju edition has been caught up in a legal battle surrounding its ownership and never been revealed to the public.
Hunminjeongeum Haerye Gansong edition consists of 33 chapters and has been designated National Treasure No. 70.
In 1997 it was listed in UNESCO's Memory of the World Program, which safeguards the documentary heritage of humanity.