OSAKA -- English teachers from Japan and South Korea who are trying to deepen international exchanges in Asia through language education have together developed a unique textbook.

The textbook, "A Rainbow over the Strait," introduces the two countries' cultures and customs in English, Japanese and Korean. It was unveiled last month by a Suita, Osaka Prefecture-based group of Japanese teachers of English.

The publication is already being used as a supplementary material in English classes by some Japanese teachers, according to Shoichi Tsuji, chairman of the e-dream-s teachers' group, which comprises about 70 high school teachers, including those from Osaka, Tokyo, Hiroshima and Kitakyushu.