The Koumi Line runs 78.9km between Kobuchizawa, Yamanashi Prefecture and Komoro, Nagano Prefecture. The line, which reaches a maximum altitude of 1,375 meters, skirts the foot of Yatsugatake mountains. Trains first ran along the whole Koumi Line in November 1935. Construction of the line was extremely difficult and local people were delighted when it was finished. The local railway has continually played a vital role in people's lives. We visit Japan's highlands in summer, where unexpected encounters are waiting.