A Christian book published in Japan in 1603 has been found at a national library in Beijing, researchers said Saturday.

The book was written by a Portuguese priest in Latin to provide other priests working in Japan with advice and was printed by a hot metal printing machine brought in by the Jesuits.

Toshiaki Koso, a professor in comparative education history at Sophia University, said after examining the book through photographs: "It was believed to be almost hopeless to find the book. It's . . . an important cultural property."