Mountain Castle and Transportation Routes Area
1.Tomogaura Road (Entrance to Yamabuki Castle)
Located on a lush hillside some distance from the closest buildings, the starting point of the 7.5-kilometer road between Iwami Ginzan and the port of Tomogaura can be difficult to spot. In the latter half of the sixteenth century, this was the epicenter of the entire silver mine. Known as the Sannai settlement, it centered on an administrative facility where officials overseeing the mine were based. Nearby stood the miners’ homes, shops, and several temples, each with its own cemetery. In this period, the mine was ruled first by the Ouchi family, which established the Tomogaura Road and built the Yamabuki Castle on high ground just outside the settlement. This hilltop fortress served to protect the mine and the road during an epoch of constantly shifting alliances and rivalries among local warlord-led families.
The Ouchi lost their stronghold and eventually conceded control over the silver mine itself to the Mohri family in 1562, but Yamabuki Castle and Sannai maintained their central position in the mining community for another four decades. In 1600 Iwami Ginzan was taken over by the Tokugawa clan, who three years later went on to unify the entire country under their banner, establishing the Tokugawa shogunate that was to rule Japan until 1867. The new government abandoned Sannai, choosing to establish its center of control in the Omori area at the foot of the mountain. The town of Omori then developed around this magistrate’s office (daikansho), while the flow of silver was directed away from the coast, to be carried instead over land to the port at Onomichi and from there to Osaka and Edo (present-day Tokyo).
Today only the stone foundations remain. The site of Yamabuki Castle, from where you can look out over the coastline of the Sea of Japan, has been reclaimed by nature. But the Tomogaura Road can still be traveled, allowing you to imagine the massive effort needed to haul heavy loads of ore through the forests on foot more than 400 years ago.
2.Yamabuki Castle Site
Iwami Ginzan was controlled by local warlords from its discovery in 1527 until the beginning of the seventeenth century.
The silver mine changed hands repeatedly during this period of constantly shifting alliances and rivalries among warrior families. The center of these battles was Yamabuki Castle, which stood on the summit of the 414-meter Mt. Yogai. The castle was built in the early 1530s by the Ouchi family; they flattened the confined summit and repurposed existing fortifications on it, constructing a rectangular keep with towers. The castle was encircled with dry moats and terraced fortifications and had high ramparts and other obstacles to discourage attack along the steep path up to the keep.
Yamabuki Castle commanded unobstructed views over the mine and its original center of activity, the Sannai settlement, as well as over the road to the port of Tomogaura on the Sea of Japan. Control of the castle was therefore key to dominion over the mine. The rival Amago and Ogasawara families managed to invade the castle on several occasions, but none was able to establish lasting supremacy until 1562. In that year, the Mohri family assumed total control over Iwami Ginzan and fortified the castle further. Yamabuki never saw a major battle again: in 1600 Iwami Ginzan was taken over by the Tokugawa clan, who three years later went on to unify the entire country under its banner, founding the shogunate that was to rule Japan until 1867. The new government chose to establish its center of control in the Omori area, and Yamabuki Castle was gradually abandoned.
Today only stone foundations and remnants of the ramparts of the castle remain on and around Mt. Yogai. The site of the main keep has been reclaimed by nature, but it is possible to make out some of the other fortifications on the summit if you know where to look. The summit commands a view of the coastline. It is about an hour’s climb from the starting point of the Tomogaura Road, but visitors should note that some sections of the trail can be difficult to traverse.
2.Battles for Iwami Ginzan
The discovery of the Iwami Ginzan silver mine in 1527 occurred during a time of great unrest in Japan. This Sengoku (“warring states”) period was an epoch of constantly shifting alliances and rivalries among local warlord families. The Ouchi family, based in the southern province of Suo (present-day Yamaguchi Prefecture), was the first to assume control of the mine. Immediately after doing so, the Ouchi built a series of castles and other fortifications throughout the area to protect their mountain of riches from rival forces. These strongholds numbered more than a dozen and included Yamabuki Castle, the mine’s main fortress, the twin forts Yataki and Yahazu that guarded the road between the mine and the port of Yunotsu, and Iwami Castle, which overlooked the passage northwest to the coastal town of Nima. These outposts were the scene of many fierce battles throughout the 1530s and 1540s, when the Ouchi repelled repeated invasions by the local Ogasawara and Amago families.
The Ouchi’s hold on Iwami Ginzan began to unravel in the 1550s, when the powerful Mohri family of Aki Province (present-day Hiroshima Prefecture) extended its influence northward. Forces led by the warlord Mohri Motonari (1497–1571) assumed complete control over the area in 1562 and went on to fortify it further, establishing a naval base outside the port of Okidomari to protect both the silver shipments from that port and the supply route to nearby Yunotsu. The Mohri controlled the silver mine for almost four decades, until they and their allies were defeated by the Tokugawa clan in the decisive Battle of Sekigahara in 1600. Subsequently, the Mohri were confined to the province of Choshu at the western end of Honshu, and the Tokugawa took over Iwami Ginzan, bringing the battles for the silver mine to an end. Led by the warlord Tokugawa Ieyasu (1543–1616), they went on to unify the entire country under their banner, and in 1603 established the Tokugawa shogunate that was to rule Japan until 1867.
3.Iwami Castle Site
Iwami Castle was a hilltop fort that in the 1500s was used to guard the main road between Iwami Ginzan and the coastal town of Nima, northwest of the silver mine. Nima was a stronghold of the warlord-led Ouchi family, which battled rival families for control over the mine from the late 1520s onward. The castle was built on the summit of Mt. Ryugan, a rocky outcrop 153 meters above sea level. The hill has steep cliffs to the south and east, making it a natural fortress. These directions were reinforced by the Ouchi, who dug a deep dry moat and built several embankments along the ridges to protect the castle keep, which stood on the narrow summit. The entrance was on the gentler-sloping north side, suggesting that Iwami Castle was mainly designed to protect Nima from enemies approaching from the south. The castle lost its significance and was abandoned after Iwami Ginzan was taken over by the Tokugawa shogunate (central government) in the early 1600s. Its site, now reclaimed by nature, can be climbed by taking a trail from the south side. In autumn, the Chinese trumpet vine (Campsis grandiflora) growing along the cliffs produces flowers that paint part of the hillside bright orange.
4.Yahazu Castle Site
Yahazu Castle was one of the two mountain outposts established in the sixteenth century to guard the road between the Iwami Ginzan silver mine and the port of Yunotsu, the mine’s main source of supplies. Located on a high hill above the north side of the road, 480 meters above sea level, it was likely built in the late 1520s or early 1530s, when the warlord-led Ouchi family controlled the area. Yahazu was much smaller than its twin, Yataki Castle, and consisted mainly of stone walls, dry moats, and embankments constructed along the ridge of an extremely confined summit, on the south side of which a compact keep overlooked the road. The fort changed hands repeatedly throughout the 1500s, as local warlords fought over the mine during a period of constantly shifting alliances and rivalries among warrior families, but lost significance after Iwami Ginzan was taken over by the Tokugawa shogunate (central government) in the early 1600s. The long period of peace that followed gradually rendered Yahazu and other medieval forts like it obsolete. The summit it occupied has been reclaimed by nature, and only isolated sections of the fortifications remain today. A trail leads up to the castle site but can be quite difficult to traverse at times.
5.Yataki Castle Site
Yataki Castle was one of the two mountain forts established in the sixteenth century to guard the road between the Iwami Ginzan silver mine and the port of Yunotsu, the mine’s main source of supplies. The castle was built in 1528 on a high hill above the south side of the road by the warlord Ouchi Yoshioki (1477–1529), who controlled the area at the time. It occupied the entire elongated summit, 634 meters above sea level, and fortifications such as stone walls and dry moats were constructed around it. The castle’s round keep, built on the north end of the summit, had an unobstructed view over the road and toward Yahazu Castle on the opposite side.
Control of the fort changed hands several times throughout the 1500s, as local warlords fought over the mine during a period of constantly shifting alliances and rivalries among warrior families, but the fort lost its significance after Iwami Ginzan was taken over by the Tokugawa shogunate (central government) in the early 1600s. The long period of peace that followed gradually made Yataki and other medieval castles like it obsolete. Little of the castle remains today, in part because the flattened area on the summit was expanded after World War II to make room for a US military radar base, which was later replaced by a broadcast transmission facility. A trail leads up to the peak; the climb takes less than an hour.
6.Yunotsu-Okidomari Road at Nishita
Now surrounded by picturesque rice fields, the quiet settlement of Nishita was once an important post town on the road connecting the Iwami Ginzan mine with the ports of Yunotsu and Okidomari. Although silver was only transported to the coast during a 40-year period in the latter half of the sixteenth century, the road was the main source of supplies to and from the mine until the late 1800s. With so much traffic passing through, Nishita’s teahouses, inns, and taverns thrived, while regular markets attracted people from nearby villages.
Local people would pray for prosperity at Kami’ichi Ebisu Shrine, which honors Ebisu, one of the Seven Gods of Luck and the patron of tradesmen. The small shrine is located at one end of the settlement. Prayers for protection against fire were said to Kannon, the bodhisattva of mercy, while other statues of Buddhist deities carved out of stone were also placed along the road to ensure safety. All these sites of worship remain today, as does the tradition of yozukuhade, a time-honored technique for drying harvested rice plants in the sun. Unique to Nishita, this practice takes its name from the word yozuku, which means “owl” in the local dialect. When the wooden frames used to dry the rice plants are full, they are said to resemble these nocturnal birds.
7.Yunotsu-Okidomari Road
The winding road between Iwami Ginzan and the ports of Yunotsu and Okidomari passes through mountains and deep forests on its way to the Sea of Japan. Established in the latter half of the sixteenth century, after the Mohri family had taken control of the silver mine, it quickly became the main road servicing Iwami Ginzan. All manner of supplies were transported from the ports to the mountain settlements around the mine, whereas silver extracted and refined at the mine traveled the other way, either loaded onto simple carts or carried by oxen.
The Yunotsu-Okidomari was initially a dirt road, but in the Edo period (1603–1867) parts were paved with stone to make it easier to travel. Quarries used to extract stone for this purpose can still be seen along the path. Although silver was carried to the coast along this road for only 40 years between the early 1560s and the first few years of the 1600s, it remained the primary route for transporting supplies to the mine until the late 1800s. Today, you can walk the entire 14-kilometer length of the old road from Omori to Yunotsu and Okidomari, but note that some sections can become difficult to traverse after heavy rain.