Japan Castle Explorer: Kinzan Castle -Time to treason (7) separation of two strong enemies-

Kinzan Castle

-Time to treason (7) separation of two strong enemies-

Overview

Name: Kinzan castle (Kinzan-jo)
Alias:
Place: Oiiri Tanba-Sasayama city, Hyogo
Type: Mountain Castle
Built: 1578
Remaining remnants: Stone walls and clay walls
Title:

Brief History

Continued from Part 6

Kinzan castle (金山城) is built over the peak of Kinzan mountain, one of about 250 meter height from hillside at the border of current Tanba-Sasayama city and Tanba city. This also means castle site is at the border of Sasayama basin and Hikami basin, two of four basins consist Tanba province (western part of Kyoto prefecture and eastern part of Hyogo prefecture).

Center of Hikami basin and Sasayama basin is about 10 kilometer apart, and although railway route detours along with Kakogawa-river and Sasayama-gawa river, a mountain road now used as Route 176 straightly connects two basin passing Kanega-saka pass just aside of Kinzan mountain. Therefore, it was suitable place to manage the transportation between two basins.

Origin of Kinzan castle

Kinzan castle was built by Mitushide Akechi (1528-1583), the regional commander of central ruler Nobunaga Oda (1534-1582) in 1578, as a tactical base exactly to separate Sasayama basin held by Hatano clan and Hikami basin managed by Akai clan.

In 1575, Nobunaga Oda who already seized current Tokai region and Kinki region fatally broke its rival Takeda clan which had been the treat to Oda clan over five years at the battle of Nagashino. Next Oda clan devastated Ikko Ikki army which seized Echizen province (Fukui prefecture) after the fall of Asakura clan then stabilized its eastern front.

Looking at the stability of its eastern front, next Nobunaga started expansion toward westward, expecting conflict with Mouri clan which held most part of Chugoku region. Nobunaga ordered his general Hideyoshi Hashiba (1537-1598, later Hideyoshi Toyotomi) to enter Harima province (Hyogo prefecture), and Mitsuhide to proceed to Tanba province.

Two strong lords of Tanba province

Tanba province was just at the next of capital Kyoto city but the situation was unstable. Originally the province was once controlled by Naito clan, which was deputy governor of the province and lord of Yagi castle (Kyoto prefecture) at Kameoka basin. But in 1565 Naito clan fought the alliance of local lords and lost their leader, then Naito clan significantly lost their power along with Shiomi clan resided at Fukuchiyama basin.

Replacing this, Hatano clan which was the lord of Yagami castle (Hyogo prefecture) at Sasayama basin and Akai clan located at Kuroi castle (Hyogo prefecture) at Hikami basin grew their power. Hatano clan formerly grew their power under their leader Tanemichi Hatano (1496-1530), and broke their master Hosokawa clan, and once lost their power but recovered under Hideharu Hatano (?-1579).

Contrary to this, Akai clan rapidly grew their power in the middle of 16th century under their leader Naomasa Akai (1529-1578). Naomasa was famous for his braveness, and broke Naito army then captured Fukuchiyama area in 1565. Next aggressively expanded its territory toward northwest and once captured Takeda castle and Konomiyama castle (Hyogo prefecture) of Tajima province.

First attack to Kuroi castle

In 1568, when Nobunaga Oda marched to Kyoto city and placed Yoshiaki Ashikaga (1537-1597), both of Hatano clan and Akai clan once followed to Nobunaga. But later looking at the break of Nobunaga and Yoshiaki, Hatano clan and Akai clan became closer to Yoshiaki as Tanba province was originally the territory of Ashikaga clan.

In 1575, based on the order from Nobunaga, Mitushide Akechi entered into Tanba province. At first Mitsuhide gathered local lords of Kameoka basin, where was the entrance of Tanba province from Kyoto city. Mitsuhide used Kamioyama castle as his temporal base and sent the order of subordination to other local lords including Hatano clan and Akai clan.

Hatano clan once expressed to follow to Mitsuhide but Akai clan did not accept it. Therefore in the winter of 1570, Mitsuhide lead his army and marched toward Kuroi castle, the main base of Akai clan passing the territory of Hatano clan. Mitsuhide built positions surrounding Kuroi castle and started castle siege.

Defeat and retreat

It seemed completely encircled Kuroi castle might fall soon. But suddenly Hatano army joined in Akechi army suddenly turned to the enemy and attacked Akechi army cooperating with Akai army. Mitsuhide once retreated and tried to restore his army, but deeply inside the enemy area and backside was also shut by Hatano army then ran away from Kuroi castle being supported by friendly lord.

It is not clear why Hatano clan suddenly left Akechi army, but there might be secret agreement between them. Hatano clan might made fake surrender to Mitsuhide and ask him to attack Kuroi castle, to lure Oda army into mountain area and defeat.

Anyway Mitsuhide lost most territories of Tanba province and once retreated to his main base Sakamoto castle (Shiga prefecture). Mitsuhide reorganized his army and tried to seize Tanba province again, but this time used more careful tactics of restraining Hatano clan and Akai clan by castles and defeating small local lords one by one.

Preparation for second attack

At this time there were many battles around Kinki region, Mitsuhide had to support Oda army at other front thus capture of Tanba province was done at the interval of such battles. Slowly but steadily the operation of Mitsuhide proceeded, then Mitsuhide at first captured eastern part of the province next to Kyoto area.

Once the backward is fixed, next Mitsuhide attacked branch castles of Hatano clan and Akai clan to encircle Yagami castle and Kuroi castle. At the same time Bessho clan which was a marital relative of Hatano clan also raised their army against Nobunaga, but soon Bessho clan was encircled at Miki castle by Hideyoshi Hashiba.

Further in 1578, Mitsuhide built Kinazan castle just at the middle of Yagami castle and Kuroi castle, to separate Hatano clan and Yagami clan. Just at this time Naomasa Akai who aggressively lead Akai clan died in ill, then the moral of Akai army significantly fell and their retainer began to turn to Akechi army.

Structure of Kinzan castle

Kinzan castle spreads T shaped peak of Kinzan mountain. Central area of castle is a rectangular one of 50 meter long and 20 meter wide, which has about two meter height stone wall at its western half where main building might exist. At the west slope of central area there is a huge shaped rock called as “Oni no Kakehashi”, which is a huge flat stone stands over the gap of the rock like a bridge.

At the east of central area there is secondary area but this is just a natural small peak and might be used as watching point. Below of hilltop area a narrow and long flat space called as riding place spreads southward over 200 meter long and ahead this there might be the main gate of the castle protected having small masugata buffer area.

Further at the south there is a flat space later used by the ground of the temple. Stone wall with stone steps is the remnant of the temple but clay wall and dry moat might keep original style of the castle. Because of narrow hilltop structure of the castle separately exist but total size and structure of the castle deserves as the castle of Oda army.

Fall of two castles and afterward

In 1579, Yagami castle finally opened under the shortage of supply then leaders of Hatano clan were executed. Next Akechi clan made total attack against Kuroi castle, then Akai clan lost their brave leader and soldiers easily fell. Mitsuhide ruined remaining small lord over the province thus could conquer Tanba province after four year struggle.

As both of Sasayama basin and Hikami basin kept by Akechi clan, the necessity of Kinzan castle was significantly declined. It might be kept as guarding point but might be abolished at the fall of Akechi clan in 1582, after the coup d’etat of Mitsuhide against Nobunaga and defeat of Mitsuhide at Hideyoshi Hashiba at the battle of Yamazaki.

Now no building remains but structure of the castle well remain on the mountain with half broken stone walls. From the central area of the castle both of Sasayama basin and Hikami basin is seen from opposite direction, and this exactly shows why this castle was built at this place. Castle remnant well expresses the strength of Hatano clan and Akai clan, and also intelligence of Mitsuhide defeating them by separation.

Continue to Part 8