Tachibana Dosetsu's noteworthy military campaign — AD 1567 Yasumimatsu Campaign (休松の戦い) — Background

Jul 2018
Hong Kong
One of the greatest military commanders I personally admired, the Otomo clan’s great general Tachibana Dosetsu (立花道雪), who was reputed the “Devil Dosetsu” (鬼道雪), “The Soul of Otomo Clan (大友之魂), “The Lightening God” (雷神), “The God of War” (軍神)…etc, was ever painfully humilitated and defeated by a not-so-famous (and almost “obscure” for the Westerners) Japanese Kyushu daimyo named Akizuki Tanezane (秋月種実) !? Indeed, this was Dosetsu and the Otomo clan’s crushing defeat ! It utterly shattered Dosetsu’s “invincible myth”.

You might tease : Aren’t you saying that Tachibana Dosetsu is one of the greatest military commanders in the Sengoku Era ? Did you actually overestimate his ability ? Virtually, greater the adverse was, greater chance the general prove his mettle. It was exactly in this battle Dosetsu exhibited his extraordinary bravery, leadership and stratagem. Despite of his failure of turning defeat into victory, he conducted the successful fighting withdrawal that prevented the Otomo army’s complete rout, showed his excellent quality as a military commander.

Background #1 — Who the hell is Akizuki Tanezane ?

The Akizuki Clan's family crest

Akizuki Tanezane (秋月種実) was the second son of the Akizuki Clan’s leader Akizuki Fumitane (秋月文種). Akizuki (秋月) was a prominent clan perched in the Chikuzen province (筑前国) since the Heian Period (平安時代) ; by the Sengoku Era, it initially submitted to the powerful Ouchi Clan (大内氏), which dominated six provinces in the central-western Japan astride Kyushu (九州) and Chugoku (中国) in the height of power and even grasped the vital trade with the Ming Dynasty (China) that brought the clan flourishing economy.

The Ouchi Clan's sphere of influence

However, in AD 1551, the sudden coup known as “The Taineiji Incident” (大寧寺の変) in which the Ouchi retainer Sue Takafusa (陶隆房) killed his liege Ouchi Yoshitaka for seizing power (大内義隆) erupted within the Ouchi Clan greatly weakened this former great power and soon embroiled into civil strife and division, combined with the growing threat of Mori (毛利) in the Aki Province (安芸国) that distracted its attention, the Ouchi clan’s control over the Northern Kyushu was drastically weakened.

Taking advantage of this rare opportunity, the neighbor great clan Otomo (大友) quickly filled the power vacuum by seizing the provinces of Buzen (豐前) and Chikuzen (筑前).

The Otomo clan seized the province of Buzen and Chikuzen

The provinces of Buzen and Chikuzen possessed a number of thriving commercial hubs. They were one of the most flourishingly economic centers in Japan. The trading port towns such like Hakata (博多) was an important linchpin and gateway linked with the regional trade with China and Korea, and also closely connected with the “licensed trade” (勘合貿易) dealed with the Ming Dynasty ! Surely Otomo Yoshiaki (大友義鎮, later known as Otomo Sorin 大友宗麟) desired to annex such the “treasure land” for his own domains to strengthen his power.

Realizing the change of tide, Akizuki Fumitane (秋月文種) turncoated to Otomo and abandoned Ouchi. But in AD 1557, he rebelled against Otomo Yoshiaki under the instigation of the “Shugoku Overlord” Mori Motonari (毛利元就). Enraged by such betrayal, Yoshiaki waged the punitive expedition with 20,000-strong army, stormed the Akizuki Clan’s homebase, Koshosan Castle (古処山城) ; Akizuki Fumitane and his eldest son & heir Akizuki Harutane (秋月晴信) were forced to commit suicide.

Yet the second son Akizuki Tanezane (秋月種実) managed to escape and seek refuge in the Mori Clan, vowed to avenge his family and restore his clan to power. Two years later (AD 1559), he successfully recaptured Koshosan Castle and recovered his clan’s lost domains thanks to the Mori Clan’s support. The Akizuki Clan was back !

Henceforth, Akizuki Tanezane became one of the bitterest foes of the Otomo Clan, and the formidable enemy of two generations of the Tachibana Clan (Dosetsu + Muneshige). He refused to kneel down to Otomo and collaborated with other native clans and the powerful Mori to forge the “anti-Otomo Coalition”.

Background #2 — Mori Motonari’s ambition turned the entire northern Kyushu into upheaval

The Mori Clan's family crest

The Mori clan's territories in circa AD 1555

In the decisive AD 1555 Battle of Itsukushima (厳島の戦い), the newly-ascended “Shugoku Overlord” Mori Motonari (毛利元就) utterly defeated Sue Harukata (陶晴賢) who took over the de facto rulership of the Ouchi Clan (though with the puppet clan leader Ouchi Yoshinaga大內義長 installed on the seat), and then easily conquered the ramshackle Ouchi Clan in AD 1557, forced Ouchi Yoshinaga to commit suicide and captured the Province of Suo (周防国) and Nagato (長門国), incorporating all the western Shugoku territories to the hands of Mori Motonari, resulted in the rapid rise of Mori to great power and the adjacency between the two powerful clans Mori and Otomo with only a narrow strait in separation.

During AD 1558-62, Mori Motonari had attempted many times to conquer the northern Kyushu from the Otomo Clan, while inciting the native landlords to rise against the Otomo supremacy, caused great deal of troubles to the Otomo Clan. At the meantime, Otomo Yoshiaki launched a series of counter-offensive against Mori for recapturing the vital Moji Castle (門司城), yet ultimately foiled ; Mori Motonari even further expanded the Mori Clan’s peripheral territories from the Moji Castle in Kyushu. The dispirited Otomo Yoshiaki entered into Buddhism and changed his name to “Sorin”, thus became the well-known Otomo Sorin (大友宗麟).

The AD 1561 Moji Campaign

Nonetheless, Otomo Sorin soon braced himself up and devised a great idea to turn the table : First of all, “bribing” the Ashigaka Shogunate (足利幕府) with large sum of gold to entice it “interfere” the business, while denouncing the Mori Clan’s blatant violation of the treaty between both clans in front of the Shogun and requesting the Shogun to “intermediate” the conflict between both clans ; simultaneously, Sorin actively communicated with Mori’s another enemy, the Amago Clan (尼子氏), intending for “pincer encirclement” of Mori Motonari from two sides. With these diplomatic movements, the situation was turning more favorable towards Otomo.

Stunned by the sudden change of situation, Mori Motonari found himself in great disadvantage and was unable to concentrate his strength to attack Amago. As a result, Motonari agreed for negotiation under the 13th Ashikaga Shogun Yoshiteru (足利義輝)’s mediation, ended with the truce between Mori and Omoto, historically known as the “Bungo-Aki Peace Agreement” (豊芸講和).

The Otomo Clan's supremacy in the northern Kyushu

However, by AD 1566, Mori Motonari who already conquered the Amago Clan by storming its homebase Gassan-Toda Castle (月山富田城), instantly turned his sight on the northern Kyushu region. As forementioned, the Province of Buzen and Chikuzen were the flourish commercial region, now the unchallenged overlord in Chugoku Mori Motonari certainly would not miss such an opportunity to grabbing that piece of “blossoming land” with now even the greater might with much enlarge territories and swelling number of troops. Not only he had the gigantic ambition and capability to achieve his goal, he also possessed the support of the “Murakami Pirate” (村上眾) which would provide him sufficient number of transport ships to ensure the maintainace of logistical capability and constant reinforcement sent across the Kanmen Strait (関門海峡) with unrivaled naval domination.

On top of that, a large number of northern Kyushu native clans had been long since desiring to get rid of the Otomo overlordship. The instigation carried out by Mori Motonari easily propelled many native landlords to change sides and turn against Otomo, culminated with the grand anti-Otomo coalition looming on the horizon. In consequence, the whole northern Kyushu degenerated into widespread rebellion and tumult that severely weakened the Otomo Clan’s control over the Province of Buzen and Chikuzen. In addition, the Akizuki Clan was rising in power, and supported the Otomo rebel Takahashi Akitane (高橋鑑種) to against his liege while getting closer with Mori. Otomo Sorin was worried of the deterioring strategic situation.

So finally, Otomo Sorin determined to exterminate this longtime menace.
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