Paper filtering techniques had been developed in Uchiyama district in the northern part of Nagano Pref. for a long time. As this Uchiyama paper is strong and does not discolor, it is favored as paper for the sliding shoji screens. The origin of the paper making is unclear but it is said that Hagiwara Kiuemon, a resident of Uchiyama village had been to Mino to learn how to make paper. After he returned home, he began making paper and taught people how to make paper. Since then the people in this district have developed their original techniques including snow-bleaching technique, in which the locally grown kozo (paper mulberry) is steamed and peeled, and then spread on the snow to bleach the fibers. As the fibers of kozo are thick and strong, Uchiyama paper is suitable for the sliding shoji screens, paperhanging, painting, and calligraphy. The production center of the present time is Mizuho district in Iiyama City. There about 90 craftsmen are working by maintaining the tradition of 400 years.