Gosannen War vs Former Nine Years' War (Zenkunen War)

After the failure of direct assaults, the Minamoto forces demonstrated doctrinal flexibility by switching to a prolonged blockade and supply denial strategy, which ultimately led to victory. The Kiyohara forces, however, remained locked into a static defense doctrine, failing to develop breakout attempts or guerrilla tactics.

Minamoto demonstrated doctrinal flexibility by learning from initial defeats, acquiring local allies, and shifting to siege warfare; in contrast, the Abe clung to the same defensive doctrine throughout the long war and failed to adapt to changing conditions.

Attrition War

Attrition War

For the Minamoto, the center of gravity was the Kiyohara's main centers of resistance—Numa and Kanezawa castles. Yoshiie concentrated his forces on these points to target the enemy's logistics and morale, and succeeded. The Kiyohara, while basing their main effort on fortified defense, failed to mount any breakout attempts.

Minamoto correctly identified the center of gravity by targeting the Abe clan's leadership and main fortress; while the Abe dispersed their striking power into tactical engagements like Kawasaki and failed to concentrate at the strategic level.

Yoshiie's most famous tactical deception was sensing the ambush from the scattered geese. Moreover, by fomenting the split within the Kiyohara clan, he lured some groups to his side—a strategic deception and diplomatic success. The civilian massacre during the siege was a brutal instance of psychological warfare.

During the siege of Kuriyagawa, Minamoto employed an indirect approach by diverting the Abe's water source; this was an effective strategic deception that forced the defenders to surrender; the Abe relied more on tactical ambushes in their own territory.

The war was characterized not by large pitched battles but by raids by mounted archers and intense archery fire against besieged castles. There was no distinct shock cavalry or artillery; victory was achieved through prolonged starvation and psychological collapse.

In Heian period warfare, firepower was limited; however, the arrow volleys, fire arrows, and subsequent hand-to-hand combat used in siege warfare created a certain shock effect; in particular, the mass assault on Kuriyagawa after cutting off its water supply broke the defenders' will to resist.

The harsh winter conditions and deep snows of Mutsu Province severely challenged Minamoto forces, especially during the Numa siege, causing frostbite and starvation losses. However, Yoshiie utilized the forested terrain around Kanezawa Castle and the siege lines to starve the enemy into submission. The Kiyohara side, despite the defensive advantage of fortified castles, failed to actively exploit the terrain.

The snowstorm during the 1057 Battle of Kawasaki aggravated the Minamoto defeat, while the spring assault on Kuriyagawa Fortress in 1062 gave the Imperial forces an advantage in climate and water resources; thus, the seasonal cycle created both opportunities and threats for each side.

As demonstrated in the 'scattered geese' incident, Yoshiie possessed a superior ability to deduce enemy hidden movements from natural signs. In contrast, the Kiyohara forces remained ignorant of Yoshiie's reinforcements and true intentions, suffering from intelligence blindness.

In the latter half of the war, Minamoto gathered more accurate intelligence on Abe positions through local agents and the governor of Dewa Province; this asymmetry formed the basis for successful tactics such as targeting the water supply during the siege of Kuriyagawa.

The Minamoto forces, through gubernatorial authority, could move relatively quickly within the province, but instead of direct assaults on enemy castles, they adopted a strategy of siege and blockade, conducting a stubborn attrition war rather than relying on maneuver. Kiyohara forces, despite having the advantage of interior lines, remained passive.

The Abe clan utilized the principle of interior lines to maneuver more rapidly in their own region and continuously confronted Minamoto in difficult terrain; Minamoto, after receiving reinforcements, managed to squeeze the Abe into their main fortress through an encircling maneuver from the outside.

Minamoto no Yoshiie's charismatic leadership and his reputation as 'Hachimantaro' (Son of the War God) fostered high morale among his own troops while instilling fear in the enemy. Among the Kiyohara, mistrust between leaders and fear of betrayal, especially after the civilian massacres, sapped their defensive will.

The young heroics of Minamoto no Yoshiie and the legend of 'Hachimantaro' maintained high morale among Imperial troops, while the successive deaths of Abe clan leaders and the destruction of their fortresses caused psychological collapse among Abe warriors.

Minamoto no Yoshiie deepened the succession conflict within the Kiyohara clan, pulling Fujiwara no Kiyohira to his side and dividing the enemy before the battle had fully joined. Additionally, the post-war redistribution of Kiyohara lands completely shattered the enemy alliance.

Minamoto no Yoriyoshi diplomatically isolated the Abe clan by drawing local powers such as the Kiyohara clan into his alliance; however, since this diplomatic success occurred within the military course of the conflict, it cannot be characterized as pure 'victory without fighting'.