Omizo Castle -Time to treason (11) deputy minister of Kinki region-

Omizo Castle

-Time to treason (11) deputy minister of Kinki region-

Overview

Name: Omizo Castle (Omizo-jo/Oomizo-jo/Ohmizo-jo)
Alias: Koukou-jo
Place: Katsuno Takashima city, Shiga

Location: 35.29264796040907, 136.01313067020237
Type: Flat Castle
Built: 1578
Remaining remnants: Stone wall
Title:

Brief History

Continued from Part 10

Omizo castle (大溝城) is located at the center of Takashima town, at the south edge of triangle shaped alluvial fan formed by Ado-gawa river at the middle of western coast of Lake Biwako. Different from eastern coast, western coast of Lake Biwako directly faces the mountains and flat area is limited, and Takashima area is major flat land of this area along with Imatsu area just at the north of Takashima area.

In addition to its rice production, Takashima area was also important as it is connected to Obama port at Sea of Japan side across Misaka-Toge pass. Obama port was a stopping port of coast side trade along the Sea of Japan and international trade, and items are brought through mountainous road to Imatsu port or Kutsuki area and sent to Kyoto or Osaka area. Including coast side road, Takashima area was a suitable place to manage these logistics.

Treason of father

Omizo castle was built by Mitsuhide Akechi (1528-1582), an important retainer of central ruler Nobunaga Oda (1534-1582), for the use of Nobusumi Tsuda (1555-1582), a nephew of Nobunaga. Originally northwestern coast of Lake Biwako was held by small local lords and temples under the effect of major warlords of Omi province (Shiga prefecture) such as Rokkaku clan and Azai clan.

In 1571, Kazumasa Isono (1523-1580) who was formerly important retainer of Azai clan and general of Sawayama castle (Shiga prefecture), surrendered to Nobunaga then was given Takashima area instead of Sawayama castle. But at the same time, Kazumasa had to accept Nobusumi Tsuda as his adopted son.

Nobusumi Tsuda was the son of Nobukatsu Oda (?-1558, known as Nobuyuki Oda) who was the younger brother of Nobunaga and lord of Suemori castle (Aichi prefecture). Nobukatsu rebelled against Nobunaga two times aiming at leader position, but was defeated at the battle of Inau in 1556 and was finally assassinated by Nobunaga at Kiyosu castle (Aichi prefecture).

Grow up as talented general

However, Nobusumi was not killed at this time and grew up then became the general of Nobunaga. Nobunaga was often said as cruel, but if having talent Nobunaga forgave person himself who attempt rebels such as Hisahide Matsunaga (1508-1577). Thus Nobunaga seemed not to fear about Nobusumi was the son of former rebel.

In 1578, Kazumasa Isono suddenly left Takashima providence and escaped, probably under the pressure of Nobunaga to leave the leader position to Nobusumi. Nobusumi became the next lord of Takashima providence, and even though small army participated in various battles as reinforcement and showed his talent.

Nobusumi also married with the daughter of Mitsuhide Akechi (1528-1582), an important general of Nobunaga. Mitsuhide aggressively sent his son and daughter as adopted son or wife to his lower colleagues to unite as supporter. Unlike Mitsuhide, other important generals such as Hideyoshi Hashiba (1537-1598, later Hideyoshi Toyotomi) or Katsuie Shibata (1521-1582) did not do such activity.

Marriage tactics to gather colleagues

Having strong relationship between retainers might bring the doubt of skeptical Nobunaga, and Hideyoshi Hashiba did not have his son had to select his successor from limited relatives thus did not have suitable sons and daughters. This became the cause of easy collapse of Toyotomi government later.

Two elder daughter married with the relative of Mitsuhide, and third daughter Tama Akechi (1563-1600, later known as her Christian name Gratia) became the wife of Tadaoki Hosokawa (1563-1646), the successor of Fujitaka Hosokawa (1534-1610) who became the lord of Tango province (north part of Kyoto prefecture) under Mitsuhide.

Furthermore, one of his sons was sent to Tsutsui clan which was the governor of Yamato province (Nara prefecture) after the fall of Hisahide Matsunaga. By this connection Mitsuhide could grasp north and east half of Kinki region.

Build of Omizo castle

Nobusumi bravely fought at various place, thus became important position of the relative of Nobunaga just next to the elder sons of Nobunaga. After the surrender of Ikko Ikki army at Ishiyama Honganji temple (later Osaka castle), Nobusumi became the commander of the temple Nobunaga might thought as future capital and Hideyoshi actually did so, and this shows the trust of Nobunaga toward Nobusumi..

Takashima area was the border of the territory of Mitsuhide against other important general of Nobunaga such as Hideyoshi Hashiba at Nagahama castle, Katsuie Shibata at Hokuriku region and Nagahide Niwa (1535-1585) at Wakasa province (western part of Fukui prefecture).

To win the favor of Nobunaga, seize the economic concession of the trade and show the authority toward other generals, Mitsuhide built Omizo castle as small but secure castle resembled to his main base Sakamoto castle (Shiga prefecture).

Structure of Omizo castle

According to the old map of the castle, central area of Omizo castle is about 100 meter long square surrounded by the water of Otomegaike lake, an inlet of Lake Biwako. At the center of central area there is a ruin of main tower which consist of 30 meter long square upper terrace and 20 meter square lower terrace.

Stone wall have gently curved corner and built by rough stones resembles to Kanbe castle (Mie prefecture), the castle of Nobutaka Oda (1558-1583), the third son of Nobunaga built at the same time. But size of stone and fineness of the curve shows advanced technology of Mitsuhide brought to the castle.

Secondary area was built at the place of current shrine and parking of the hospital, and castle town spreads north of the castle where is still encircled by narrow waterway and many old houses remain. Castle was at the next of Omizo port, and had strong character of water castle.

Slip of Nobumori Sakuma

In 1580, Ishiyama Honganji temple where Ikko Ikki army resisted against Nobunaga over 10 years finally opened it and surrendered to Nobunaga. At this time Nobumori Sakuma (1528-1582), a veteran general of Nobunaga from a small lord, was the commander of encircle army and had the largest troops among Oda clan.

However, after the surrender of Honganji temple, suddenly Nobumori Sakuma was expressed being blamed for too much cautious tactics for Honganji temple. His predecessor Naomasa Ban (?-1576) died at the battle against Honganji temple by aggressive tactics and his relative were expelled, thus Nobumori might chose safety tactics but Nobunaga did not accept it.

Furthermore, there was no front to allocate Nobumori after the battle. At Chugoku region Hideyoshi Hashiba already suppressed Mouri clan, and at Hokuriku region Katsuie Shibata was superior to Uesugi clan. For Takeda clan Nobutada Oda (1555-1582), the successor of Nobunaga already faced.

Power and weakness of Mitsuhide

Sakuma clan had many territories at various province including Owari province and Mino province, the main territory of Oda clan. It was necessary to reorganize the troop and territory of Oda clan and it was a good opportunity by disappearance of the enemy. In the notice of expel from Nobunaga to Nobumori, Mitsuhide was applauded to won the honor of the public.

After the slip of Sakuma clan, Mitsuhide absorbed the generals of Kinki region and became the regional commander of Kinki region. Different from now, the economic power of Kinki region was far supreme against Kanto region, and Mitsuhide could control such interests. Mitsuhide became the deputy minister of Kinki region and highest retainer of Nobunaga. In 1581 Mitsuhide served as the chief of military parade at Kyoto city and showed his authority to the public.

But Mitsuhide had same risk as Nobumori Sakuma. Once Mitsuhide was thought as not necessary, his huge troop and economic interest might be the target of confiscation. Beside, compared with nominal troops, direct territory was limited to middle size Tanba province and small part of Omi province, then relied on the colleagues attached from Nobunaga.

Death in indignation of Nobusumi and afterward of castle

Nobusumi Oda served as the lord of Omizo castle by 1582. But when Nobusumi prepared invasion to Chosokabe clan at Shikoku island with Nobutaka Oda and Nagahide Niwa (1535-1585) at Osaka castle, Mitsuhide raised army against Nobunaga and killed him at the incident of Honnoji.

Nobusumi directly did not have relation to the revolt of Mitsuhide but was suspected for collaboration by marital relationship. Nobutaka Oda and Nagahide Niwa attacked Nobusumi under suspect of betrayal and Nobusumi was killed. Coincidently father and son both died under the suspect of betrayal of Nobunaga.

After the fall of Mitsuhide, next ruler Hideyoshi Toyotomi placed several generals as the commander of the castle. But Hideyoshi built Otsu castle (Shiga prefecture) in 1586, and the importance of Omizo castle decreased. Some building were brought to Minakuchi Okayama castle (Shiga prefecture), and finally Omizo castle was abolished in 1616 but remained as domain office of Wakebe clan by the end of Edo era.

Today most shape of the castle was lost by land reclamation or development, but half broke main tower basement remains along with Otomegaike inlet. At the side of the castle, old town keeps their atmosphere at L shape of east and westward formerly consists of castle town, and north and southward as road side town. Remnant of half broken magnificent main tower basement lonely remains resembles to its master who was hoped his talent but died in indignation.

Continue to Part 12