Handwritten manuscripts of four early works by renowned Japanese novelist Yukio Mishima (1925-1970) have been discovered, a literature museum in Kyushu said Friday.

The museum in the city of Kumamoto said the four works include Mishima’s debut piece titled “Hanazakari No Mori,” which he wrote in 1941 as a 16-year-old junior high school student. The short story was published in a literary magazine that year.

The manuscript of “Hanazakari No Mori” has the signature of Mishima’s real name — Kimitake Hiraoka — on the first page as well as his pen name, Yukio Mishima. This is believed to be the first use of the pseudonym.

In addition to the 56-page manuscript of Mishima’s debut piece, two other short stories and an 11-page essay were found.

The manuscripts were among the possessions of the late literary critic and scholar Zemmei Hasuda, and were donated to the museum by his family.

Hasuda, who died while fighting overseas in 1945 during World War II, had close ties to Mishima. The whereabouts of the manuscripts were forgotten after he left for the war.

The discovery is “very significant for research” about both Mishima and Hasuda, a museum official said, adding that while the manuscripts cannot be made public for now due to copyright reasons, the museum is looking into its options.

Mishima wrote fiction, plays and essays. His famous works include “Spring Snow,” “Confessions of a Mask” and “The Temple of the Golden Pavilion.”