Collapse on Tanomo in Tottori


Yamanaka Yukimori

Inaba Province

Takeda Takanobu

Date:  8/1 of Genki 3 (1573)

Location:  Koshikiyama Castle in Tottori in the Ōmi District of eastern Inaba Province

Synopsis:  After the Amago Revival Army led by Yamanaka Yukimori encroached on the territory governed by Takeda Takanobu in Inaba Province, Takanobu decided to confront them at Koshikiyama Castle.  In the course of a failed assault, Takanobu’s forces became ensnared in a pincer attack that resulted in their near annihilation.

Commanders:  Yamanaka Yukimori, Akisato Samanojō

Forces:  Approximately 140 to 150 + unknown number led by Akisato Samanojō

Losses:  Unknown

Commanders:  Takeda Takanobu

Forces:  Approximately 400 to 500 mounted soldiers

Losses:  Near complete annihilation, with Takanobu escaping to Tottori Castle

The Collapse on Tanomo in Tottori occurred on 8/1 of Tenshō 1 (1573) in Inaba Province and was waged between the Amago revival army led by Yamanaka Yukimori and an army comprised of kokujin from Inaba led by Takeda Takanobu.  The term tanomo means the surface of a rice paddy, and, as used in the name of the battle, refers to the timing of the conflict on the autumnal equinox known as hassaku, or the first day of the annual rice harvest.  The battle was waged at Koshikiyama Castle in Tottori in the Ōmi District of Inaba.


From the third to fourth months of Genki 3 (1572), Yamanaka Yukimori, the leader of the Amago revival army, was incarcerated by the Mōri army at Odaka Castle in Inaba Province after failing during the First Campaign to Revive the Amago Clan waged by the remnants of the Amago clan against the Mōri in Izumo Province.  Yukimori, however, managed to escape, going underground in Tajima Province to plan another attempt to revive the Amago clan, summoning former retainers of the Amago with the aim of invading Izumo again.

Early in 1573, the Amago revival army led by Yukimori departed Tajima to invade Inaba and captured Kiriyama Castle in the Ōmi District.  Based from this location, the forces engaged in battles across the area, expanding their power through a series of victories.  Yukimori and his army used Inaba as a foothold from which to advance to the west, aiming to recapture Izumo Province.

At this time, Inaba was governed by Takeda Takanobu, the lord of Tottori Castle.  A decade earlier, in 1563, Takanobu prevailed in battle against the former lord of Inaba, Yamana Toyokazu.  Through an alliance with the Mōri clan, Takanobu had since asserted his authority across the province.

After expanding their influence to the west, Yamanaka Yukimori and his army moved their base to Koshikiyama Castle located near Takanobu’s base at Tottori Castle.  Upon learning of these developments, Takanobu committed to the elimination of Yukimori and the Amago revival army.  On 8/1 of Genki 3 (1573), Takanobu led a contingent of 500 mounted soldiers from Tottori Castle and marched toward the base of the Amago revival army at Koshikiyama Castle.

Course of events

In response to the advance of Takanobu’s army, Yukimori and the Amago revival army adopted a strategy to hole-up in Koshikiyama Castle.  Meanwhile, Takanobu’s army approached the western side of the castle which had relatively light defenses, commencing their assault.

In the course of the assault, as Takanobu’s troops approached the moat surrounding the castle, soldiers from the Amago revival army laying in wait launched an all-out counterattack by shooting arrows, firing arquebuses, and rolling large boulders toward the attacking forces.

The ferocity of this counterattack caused Takanobu’s army to fall into disarray.  Having decided that it would be futile to continue the fight, Takanobu suspended the assault on the castle and commenced a withdrawal of his forces.

Forces led by Akisato Samanojō, however, were positioned below the castle so Takanobu’s forces could not withdraw.  Prior to the battle, Samanojō had been instructed by Yukimori to block the path of retreat for Takanobu’s army.

While Takaknobu’s soldiers clashed with Samanojō’s army, between 150 and 160 mounted soldiers led by Yukimori charged Takanobu’s men from the rear, forming a pincer attack with Takanobu caught in-between Samanojō and Yukimori.  Amidst severe losses, the surviving members of Takanobu’s army fled in defeat to Tottori Castle.


In this battle, Takanobu’s army incurred significant losses, with dead soldiers littering the road over a distance of approximately four kilometers from Koshikiyama Castle to Tottori Castle, making it even difficult to traverse.  As a result, Takanobu experienced a major decline in power.

Meanwhile, owing to their victory over Takanobu, Yukimori and the Amago revival army wielded greater authority in Inaba and expanded their base of power.

At the end of the ninth month, Yukimori and the Amago revival army attacked Takanobu’s base at Tottori Castle in an event known as the Siege of Tottori Castle by the Amago Revival Army.  The besieging forces took control of eastern Inaba and succeeded in establishing a foothold from which to fight for the revival of the Amago family.