was not clearly stated," Mizoguchi said in a statement. Shimane Prefecture claims the Sea of Japan islets fall under its jurisdiction.

The only territorial dispute specifically mentioned in the new guidance referred to the four Russian-held islands off Hokkaido.

In Seoul on Friday, South Korean Foreign spokesman Moon Tae Young said the new manual "could cause negative effects on developing future-oriented relations between South Korea and Japan by infusing wrong territorial perceptions into Japan's future generations."

Moon also stressed that the islands belong to South Korea "no matter what claims Japan makes."

Senior Japanese vice education minister Kan Suzuki said the new teaching guides do not mention Takeshima because the ruling Democratic Party of Japan is trying to make the guides and guidelines shorter and simpler in order to give more discretion to schools.

The government should not care too much about other nations' opinions when deciding how territorial disputes should be explained to students, Suzuki said.

There are currently 14 certified high school geography textbooks available in Japan, 11 of which mention Takeshima.

Yonhap news agency reported that South Korea plans to call in Japan's ambassador to Seoul to file a protest. Moon said no decision has been made on whether to summon the envoy.

The rocky cluster of islets has long been a source of discord between Seoul and Tokyo, which once ruled South Korea as a colony.

When Japan announced the junior high school teaching manual last year, South Korea temporarily recalled its ambassador to Japan in protest.