Thanks to its high quality, the company's float sheet glass was increasingly being used in place of regular glass. In 1972, anticipating strong future demand, the company decided to create a third jumbo float furnace at the Maizuru Plant. Construction was put on hold when the oil crisis struck in 1973, but resumed in 1977. The inaugural kindling took place in May the following year, and production commenced at Maizuru Furnace no. 5 in June. With a daily melting capacity of 600 tons, it was the largest furnace in Japan at the time.