The Hokuriku Shinkansen Line, which connects Tokyo and Kanazawa, was opened as an extension of the Nagano Shinkansen Line linking Tokyo and Nagano. The newly opened section of the line, which is an extension beyond Nagano to Kanazawa, has many tunnels because of high altitudes and rugged topography. Shinkansen vehicles travel at high speeds that peak at 260 kilometers an hour in very severe weather conditions during winter. Therefore, various functions, including safety, as well as high levels of sound- and thermal-insulating properties, are required of the window glass of the Shinkansen.