Visitors looking at acrylic panels inscribed with characters from the book Hunminjeongeum at an exhibition yesterday at the National Hangeul Museum in Seoul. The event was organised to mark the 620th anniversary of the birth of King Sejong, who invented hangeul (the Korean alphabet) in 1443. Hunminjeongeum, published by King Sejong, is a book that gives detailed explanations and examples of each letter of hangeul.