Mt. Shōji is a small mountain located behind Besshi Copper Mine Memorial Museum. The mountain was also the site of a castle that saw much fighting.

Rising up from the museum is a flat-topped ridge. Atop this ridge is a tall brick chimney, standing about 20 m high. A footpath, originally a road for ox-carts, goes up to the chimney through attractive trees. The chimney stands alone on a flat part of the hill. Next to it is a square of bricks embedded in the ground, indicating the size of the chimney at its top. There are cherry trees planted around, which blossom in early spring. The mountain is generally known as Chimney Mountain. You can look out over the city of Niihama to the Seto Inland Sea and the mountains behind. Near the start of the trail is a fine statue of a man in traditional clothing smelting copper the old way.

The chimney once belonged to the Yamane copper smelter built at the foot of the mountain in 1888. The mountain was entirely bald then. A 60 m flue went straight up the mountain from the smelter to the chimney, which carried the sulphur dioxide smoke into the air. However, downdrafts from the mountains behind carried the smoke into the rice fields of Niihama below, causing the farmers to complain. The chimney is considered the oldest heritage of the heavy chemical industry in Japan, and is registered as a national tangible cultural property.

The mountain continues up to a peak which was the site of Shōji Castle. The exact  age of the castle is unknown, but it was built by the Kaneko Clan during the Northern and Southern Dynasties period. In 1369, one of the Kōno clan manned the castle with over 700 horses, and resisted takeover by the Hosokawa, but was ultimately defeated.

In 1585, Toyotomi Hideyoshi ordered the invasion of Shikoku. The Kaneko clan resisted, both at Shōji and Kaneko Castle, but they were defeated by the forces of Kobayakawa Takakage, ending the influence of the Kaneko clan. Nothing remains of the castle today, although there’s a commanding view from the top of the mountain.