In 1567, Oda Nobunaga led an attack against the Saitō clan of Mino Province. The clan headquarters and administrative center for Mino Province was Inabayama Castle, a mountain fortress atop Mount Inaba (in present-day Gifu city). As Saitō Tatsuoki, the daimyo of the clan, had shown himself to be a cowardly and ineffective ruler, Takenaka Hanbei had staged a coup and took command of the castle and its garrison. Although Tatsuoki was allowed to remain the titular head of the clan, he contributed nothing to the outcome of the battle. When the Oda army entered Mino, Hanbei prepared the garrison for the defense of the castle.
According to the Shinchō kōki (or The Nobunaga Chronicles), preparations for the battle began on 13 September 1567 (Eiroku-10 year, 8-month, 1-day). Nobunaga entered the area, made contact with allies, and the core of Nobunaga's army of about 5,000 troops crossed the Kiso River. As the troops assembled on the far shore, Nobunaga sent two messengers, Murai Sadakatsu and Shimada Hidemitsu, to three of the Saitō clan's top vassals, known as the Mino Triumvirate, asking for their cooperation in the upcoming battle. Mino warlords that Kinoshita Hideyoshi had persuaded to defect brought additional troops to Nobunaga's banner.
As the forces loyal to Nobunaga moved across the plain, several skirmishes were fought in a futile effort to turn the invading forces. Nobunaga's forces then entered the town of Inoguchi, which lay below Inabayama Castle. To clear the field of view and provide space for the besieging army, Kinoshita Hideyoshi's vanguard set fire to the town. As some soldiers took positions on Mount Inoguchi and a nearby ridgeline, the main army positioned itself before Mount Inaba to begin the siege. The greatly augmented army, now bristling with the flags of the Saitō clan's former vassals and allies, bewildered the castle's defenders. During the days that followed, Kinoshita dispatched men to gather intelligence, especially from peasants willing to help. Kinoshita met with a local resident, Horio Yoshiharu, who showed him a little-known path that led up the north slope of the mountain. The north slopes below the castle were so steep that assault by a large force was considered impossible,and was thus effectively ignored by the defenders at the advent of battle.
It is uncertain exactly what happened on the battlefield between 14-5 September. Given what is known of Nobunaga's aggressive fighting style, the prevailing siege tactics of the day, the layout of the Japanese castle, and the events that followed, it can be inferred that Nobunaga's forces pressed their attack and probably breached the outer defenses of Inabayama Castle. It is known, however, that Kuroda Kanbei, considered a talented strategist, was charged with directing and coordinating the main attack. It is also certain that Kinoshita Hideyoshi devised a plan in which a small force would scale the north face of the mountain, enter the castle, and rush to open the gates for the besieging army. Nobunaga approved and charged Kinoshita with leading the raid. For his team Kinoshita selected Horio Yoshiharu, Hachisuka Koroku, and five or six other men to accompany him. On 26 September Nobunaga was so confident of Kinoshita's plan and the outcome of the battle that he had an heraldic partition erected on the battlefield where he held a meeting with his top officers and allotted tasks pertaining to the re-construction of the castle following the battle. He also greeted the daimyo of the Mino Triumvirate, who were stunned by his audacity, and offered them sake.
On the night of 26 September Kinoshita gathered his team and, concerned over the late summer heat and the exertions in store, provided them with gourds of fresh water. Horio Yoshiharu then guided Kinoshita Hideyoshi and the small assault force around to the back of the mountain, where they climbed the steep slopes by the light of a full moon. At dawn, while Kinoshita's mission was in progress, the main force under Kuroda Kanbei proceeded with its attack on the castle.
Sometime after dawn, Kinoshita's team infiltrated the castle, set fire to a storehouse and the powder magazine, and then rushed to open the front gates, cutting down whomever got in their way. With explosions erupting from the powder magazine and the other building burning fiercely, the castle defense quickly devolved into chaos, as the shocked and exhausted defenders thought they were under a full-scale attack from behind. Kinoshita's men, filthy from the night's exertions and brandishing bloody swords as they rushed across the main courtyard, added to the impression. The castle garrison was thrown into complete disarray as men were pulled from theparapets to face the nonexistent assault, while others threw down their weapons and surrendered. When Kinoshita's team had attained the gatehouse they tied their gourds to spears and waved them to their allies below to signal they were in position, whereupon Kuroda's infantry charged the open gates and overran what was left of the castle's garrison. While Kuroda's men mopped up the last of the resistance, Kinoshita's team found a place to rest while Horio Yoshiharu passed around a large gourd of sake he had taken from the castle's supply. By the end of 27 September 1567 Inabayama Castle had fallen and the remaining lords of Mino province formally surrendered to Nobunaga.
In about two weeks' time Nobunaga had entered the sprawling Mino Province, raised an army, and conquered the ruling clan in their mountaintop castle. Following the battle the Mino Triumvirate, awed by the speed and skill of Nobunaga's conquest, permanently allied themselves to Nobunaga. Nobunaga had the castle repaired and renamed it Gifu Castle. The castle-town of Inoguchi was likewise renamed Gifu, after the mountain from which Wu Wang launched his campaign to unify China. Nobunaga had a lavish manor built at the base of the castle mountain. He then transferred his primary base and residence from Komaki Castle to Gifu, from which he would launch his historic march on Kyoto the following year. He continued to use Gifu Castle as his primary residence and headquarters until he moved into the partially completed Azuchi Castle in 1575.
Saitō Tatsuoki survived the battle, though there are at least two accounts of how he managed this. In one account, Tatsuoki abandoned the castle the night before the final attack, took a boat, and fled down the Sunomata River. In another account, following the breach of the main gate, Hideyoshi dispatched a messenger to the main tower, where Tatsuoki and his entourage were cornered, with assurances of leniency if the Saitō holdouts would surrender. Tatsuoki accepted the offer and, with Nobunaga's troops forming two lines, Tatsuoki marched out of the main tower with his family and retinue. In any event, Tatsuoki eventually found his way to Nagashima, Ise Province. He lived in exile for a while, but eventually sought refuge with Asakura Yoshikage. He was killed in the Battle of Tonezaka, at the age of 26, in 1573.
The efforts of Kinoshita Hideyoshi as the mastermind of the victory were recognized by Nobunaga and his status rose accordingly. After the battle Kinoshita was promoted in rank and made lord of three districts in the northern part of the newly conquered Mino province, and not long afterward took the surname Hashiba. When Nobunaga later gave him a field command, Hideyoshi used an image of a golden gourd as his battle standard, in commemoration of his success at Inabayama Castle. In time he would change his surname again, to Toyotomi. Kuroda Kanbei, who led the frontal attack, and Takenaka Hanbei, who directed the castle's defense, would both eventually serve Toyotomi Hideyoshi.
Source: Wikipedia
