Circumstantial evidence has surfaced that Japan had concealed lists of crucial Korean cultural assets that it smuggled out of the peninsula during the 1910-45 colonial period, when the two countries were engaged in negotiations over their return to Korea in the 1950s-60s.

The bilateral talks over the stolen items proceeded as the two countries engaged in negotiations over the normalization of their relationship, which concluded in 1965.

According to a recent ruling by an appeals court in Tokyo, the Japanese government apparently sought to return only the less valuable items to Korea, while withholding highly valuable ones. The ruling came after a Japanese civic group in 2012 demanded the disclosure of diplomatic dossiers concerning all normalization negotiations between Seoul and Tokyo.

Seoul’s Foreign Ministry vowed to step up diplomatic efforts to recover the stolen assets.

“For this issue, we need to check how they were illegitimately taken out of the country, and review it based on bilateral and multilateral treaties, and international law,” ministry spokesperson Noh Kwang-il said at a press briefing. “We will put forth every diplomatic effort to bring back the illegitimately smuggled items.”

Having obtained the court ruling, Yonhap reported that in 1963, when the normalization talks were in full swing, Tokyo inventoried 852 ancient Korean books, and separated out the valuable ones before returning only the unimportant ones to Korea.

In a court statement, the Japanese Foreign Ministry was found to have expressed concerns that should the list of the withheld books be disclosed, Korea would demand their return in future negotiations. Based on the statement, an appeals court in Tokyo ruled last Friday against the disclosure of Tokyo’s sensitive documents.

In another court statement, Japan’s Foreign Ministry director in charge of Northeast Asian affairs said that Tokyo could not make the lists of the stolen books public as the disclosure would hurt bilateral relations. The statement was issued last year after a Tokyo district court ruled in October 2012 that documents concerning the lists should be revealed.

The statement noted that the documents carried information about how and from where the books were obtained, as well as their prices. It also said that should the documents be disclosed, Seoul could demand renegotiations over the unreturned books.

The statement added that although the documents included scholars’ “assumptions” about how the books were smuggled out, it was easy to predict that such assumptions could lead the Korean government and its people to form negative views about Japan.

According to the Overseas Korean Cultural Heritage Foundation, 66,824 assets ― some 43 percent of the total 156,160 overseas Korean cultural assets ― are in Japan.

According to a “cultural cooperation” appendix to the 1965 Korea-Japan normalization treaty, Japan handed to Korea more than 1,432 pieces, some 32 percent of all items that Korea wanted to bring back home. In 2011, Japan under the Democratic Party government returned 1,205 Joseon-era royal protocol books.

Seoul officials say the appendix on cultural cooperation does not state that the bilateral issues over stolen cultural heritage have been settled with the normalization treaty. The appendix states that Seoul encourages Tokyo to return the smuggled items to Korea as the return would help enhance bilateral cultural cooperation.

By Song Sang-ho (sshluck@heraldcorp.com)