Sunomata Castle: The Castle That Was Built on a Single Night

Sunomata Castle stands at the confluence of the Sai and Nagara rivers, in the city of Ōgaki in Gifu Prefecture. It’s a typical Japanese castle with a strong foundation of stone and a multi-storied wooden building on top with a gable roof and decorated eaves. As far as castles go, Sunomata is very small, but it has a big story. Legend has it that the Sunomata Castle was built during the course of a single night.

Sunomata Castle, also known as Ichiya Castle (or the “one night castle”), was constructed in the mid-16th century by Toyotomi Hideyoshi, one of the generals of the powerful feudal lord Oda Nobunaga, during the buildup to the siege of Inabayama Castle in 1567.

Sunomata Castle in Ōgaki. Photo: mTaira/Shutterstock.com

Oda Nobunaga’s biggest rival was the Saitō clan of the neighboring Mino Province, despite the fact that he was married to the daughter of Saitō Dōsan, the rival leader. Indeed, his marriage was a political truce his father forged in the hope that it would end the rivalry between the two clans.

Saitō Dōsan originally planned to pass his inheritance to his eldest son Saitō Yoshitatsu, as any father would have. But when he saw the grace with which Oda Nobunaga ruled his kingdom, he started thinking that maybe his son-in-law would be a more deserving candidate than his own sons. When Yoshitatsu learned that his father was planning to give away his inheritance, he seized power by a coup d'etat in 1556, and then murdered his father as well his younger brothers.

Oda Nobunaga.

In 1561 Yoshitatsu died after a long illness and his son, Saitō Tatsuoki, succeeded to the leadership of the clan. However, Tatsuoki was young and incapable of effective leadership. He was viewed with contempt by his subordinates, and even despised by the local peasantry. Taking advantage of this situation, Nobunaga convinced many Saitō retainers and warlords in the Mino area to abandon their incompetent master, and defect to the growing alliance under the Oda clan, promising them rewards for their support.

In anticipation of the upcoming campaign, Nobunaga assigned his trusted retainer Toyotomi Hideyoshi, who would go on to become one of the most powerful men in Japan, to build a castle between the fork of the Sai and Nagara rivers where they both converged at Sunomata. This new castle would serve as a staging point for the Oda forces from where they could launch an attack against Inabayama Castle. However, Sunomata was located within enemy territory and any construction work was likely to be hampered by Saito’s forces. But Hideyoshi had a plan.

Toyotomi Hideyoshi.

Hideyoshi began by felling trees on the opposite bank of the Nagara River and fashioned them into prefabricated sections of the castle walls and towers. These were then floated down the river on rafts and re-assembled at Sunomata within the course of a single night. Early next morning when Saito Tatsuoki gazed down from Inabayama Castle on the stout new fort, which had seemingly appeared overnight, a chill went down his spine. In reality, the “fort” was little more than a skeleton with a façade, intended to psychologically intimidate, surprise and demoralize the enemy. Stalled by the enemy's caution, Hideyoshi’s men were able to quickly transform the fragile framework into a functioning fortification, and then into a complete castle.

Hideyoshi climbing the steep slopes of Mount Inaba (now Mount Kinka) to lead an assault on Inabayama Castle. Woodcut print by Yoshitoshi (1885)

In 1567, with Hideyoshi’s assistance, Nobunaga was able to launch the conclusive assault on Inabayama Castle. His army of around five thousand troops crossed the Kiso River and marched straight to the castle town of Inoguchi (now Gifu city) attracting the support of many Saito retainers along the way. The defenders were demoralized to see the banners of Saito retainers among the attacking army, but the mountaintop castle was still in a nearly impregnable position. The siege took about two weeks. Towards the end of the siege, Hideyoshi led a small party up the steep cliffs of Mount Kinka, infiltered the castle from the unguarded rear, and threw open the front gates, allowing the attacking forces to enter. After Tatsuoki was defeated, Nobunaga claimed the castle and renamed it Gifu Castle.

Gifu Castle. Photo: hayakato/Shutterstock.com

The current castle at Sunomata is a reconstruction built in 1991, modeled after the nearby Ogaki Castle. The castle serves as a museum highlighting its history and importance. Inside, one can see a model of what the castle would have really looked like in reality along with samurai armor pieces and weapons of that time. The castle is also one of the best sites to view cherry blossoms during spring as the banks where the castle is located are covered with hundreds of cherry trees.

Sunomata Castle. Photo: mTaira/Shutterstock.com

References:
# Danny Chaplin, Sengoku Jidai Nobunaga, Hideyoshi, and Ieyasu: Three Unifiers of Japan
# Chris Glenn, Sunomata, The One Night Castle, Japan Travel
# Wikipedia