Chapter 107: Asiatic Northern War Part VI - The Battle of Alchuka Plains
Despite the fall of Haishenwei from Japanese hands, the main Jin army had been preoccupied long enough for Bahai to finish raising a new army and then depart Nurgan, making camp not far from Kuromatsu Castle. This meant that between Kuromatsu Castle and Haishenwei, the Amur Jurchens and Japanese possessed a total of 35,000 men. The Amur-Japanese coalition began taking advantage of this newfound mass of manpower, with Bahai recapturing Jixi in the coming month and his men regaining all lost territories between Kuromatsu Castle and Lake Khankai-Omo [1]. In a poignant moment during this particular campaign, Bahai returned to the battlefield where his father had been killed in the beginning of the war and prayed for those who had fallen on that day with his men before giving the remaining skeletons strewn all around proper burials and final rites. In any case, the situation alarmed Gutai and he attempted to blunt and reverse the momentum of the enemy by marching directly towards Bahai’s main army. However, he was forced to stop after rumors of a new Japanese army led by Kaga Nagaaki marching towards the area spread. Indeed, Nagaaki had marched northwards from Kanazawa to Sakata in the spring months and taken transports from there along with his army far from the reach of Joseon ships to the mainland. However, he was still quite far away at the time, and the specter of his presence only gave him more time to march towards the positions of Gutai and Moritora, leading an army of 15,000.
Flush with confidence, Bahai plotted to carve a path through the heart of the Lesser Jin khanate towards its capital of Hetu Ala. To that end, he sought to capture the interior Jin stronghold at Alchuka Hoton [2]. He sent a letter to Moritora, requesting that he send 3,000 Japanese men experienced in siege warfare and artillery operations to assist with his planned siege of Alchuka Hoton. Moritora himself would stay in the area to wait on Nagaaki’s army of 15,000 and to stall any moves by Gutai or any other Jin-Joseon forces in the area. In response, Gutai began sending messengers across his own khanate, Joseon, and Amur territory occupied by his warriors to move towards the main army and help inflict a final defeat upon the Japanese and Amur Jurchens. One of these messengers reached the army besieging Russian-controlled Albazin, and this force withdrew from their endeavor to move southwards. On his way back to his sovereign, however, the khan’s messenger was intercepted and captured by the Japanese. Upon learning the information from the messenger after the latter was tortured and beaten, Moritora retreated north to Kuromatsu Castle to strengthen its defenses and prepare a surprise attack upon the northerly enemy. Gutai took advantage of this defensive withdrawal and the departure of Bahai’s main army, pouncing upon Jixi and retaking it in 2 days.
State of the war, summer 1667
Initially, Gutai hoped to wait for Jin and Joseonite reinforcements at Jixi. However, Nagaaki arrived in the army, boosting the enemy’s manpower and increasing the precarity of Gutai’s position. Therefore, Gutai changed plans and instead left Jixi only days after he had recaptured it, leading his men straight towards Alchuka Hoton and Bahai himself. Although this would leave the Jin-Joseon army marching south near the Amur River alone against the Japanese, the move would allow Gutai to unite with the main Joseon army in the area led by Shin Ryu. Furthermore, a Jurchen force of 7,000 led by veteran general Ebilun had already arrived in the vicinity of Alchuka Hoton, although they had avoided direct combat with Bahai’s besieging force so far. As for Bahai, whose imminent encirclement by Gutai, Shin Ryu, and Ebilun was as of yet unknown to the khan of the Amur Jurchens, he had been busy engaging with the garrison in Alchuka Hoton and had successfully captured the outer elements of the fortress. The rapidly incoming Battle of Alchuka Plains, however, would inevitably force him to switch his focus to the field armies of his enemy.
Not long after the Japanese armies of Sakuma Moritora and Kaga Nagaaki made contact, news of Gutai’s departure towards Alchuka Hoton reached them, and a decision had to be made. They would both have to defend Kuromatsu Castle from the northern enemy force and rescue Bahai from Gutai’s encirclement strategy. A decision was made to split the Japanese force in the region to respond to both. The bulk of the Japanese army, around 20,000 and led by Nagaaki, would head towards Alchuka Hoton while the remainder of approximately 8,000 men would stay and confront the enemy just north of Kuromatsu Castle and would be led by Moritora. Nagaaki, now the official commander in chief of Japanese land forces on the Asiatic mainland as a blood member of the Oda clan, began his move in early September, accompanied by veteran generals like Sassa Katsutane and Mogami Yoshisato. He himself possessed a good deal of military experience from the Manji War despite his youth, having taken over for his father Tomoaki after the latter succumbed to his wounds at the Battle of Uonuma. His army also included 500 members of the rebuilt Konoe cavalry as well as the entirety of his father’s elite musketeers that had contributed to Moritora’s only loss on the battlefield at Uonuma.
On the plains surrounding Alchuka Hoton, meanwhile, Gutai had consolidated the forces of the Lesser Jin and Joseon, with a total of 47,000, composed of 28,000 Jin Jurchens and 19,000 Joseonites. Outnumbered by more than 2 to 1, Bahai and his entire cause seemed poised to be wiped off the map. The day before the Jin-Joseon coalition was planning to attack the Amur Jurchens, though, Nagaaki arrived with his army and had already begun to coordinate with Bahai through a messenger that had ridden ahead. The battle therefore would be delayed by 4 days and would take place on August 18th, 1667. Against the Jin-Joseon army, Amur-Japanese field forces numbered 38,000 including 21,000 Amur Jurchens and 17,000 Japanese [3] with 5,000 men continuing the siege upon Alchuka Hoton. What would be known as the Battle of Alchuka Plains would actually consist of 2 separate and simultaneous engagements. The smaller of the two pitted Ebilun’s 7,000 against a similarly sized force led by Mingginu, predominantly composed of Amur horse archers but also incorporating some Japanese samurai cavalry units.
The bigger engagement would directly pit the rulers of the khanates against one another, Gutai of the Lesser Jin and Bahai of the Amur khanates, together with their allied forces. On the Amur-Japanese side, the Japanese infantry was positioned in the center and was commanded by Kikkawa Hiroyoshi while the Japanese left wing and Jurchen right wing were cavalry-heavy, led by Sassa Katsutane and Jurchen general Mordaja respectively. Finally, Kaga Nagaaki and Bahai surrounded themselves with Jurchen reserves behind the infantry formation. The Japanese infantry was jutted out compared to the wings in an inverse crescent formation. Meanwhile, on the other side of the battlefield, the main Jin-Joseon infantry mass held together the Joseonite right wing and the Jurchen left wing of, led by Shin Ryu and Gutai’s brother Sooge respectively and mostly made up of heavy and light cavalry. The khan himself would survey the combat from the back, surrounded by reserve Jurchen horse archers. Additionally, a frontline of horse archers from the retinues of the Jurchen chiefs that had joined the Joseon army 3 decades earlier screened the Jin-Joseon infantry. They, led by Manggultai’s descendant Sahaliang, were tasked with softening Japanese ranks ahead of the Jin-Joseon infantry, the latter who then would advance upon the Japanese.
Main engagement of the Battle of Alchuka Plains (Salmon = Japanese, Green = Amur Jurchen, Blue = Joseon, Brown = Jin Jurchen)
The battle began with a salvo of cannonfire from both sides followed by the commencement of the Japanese infantry’s steady march towards the Jin-Joseon army. As planned, Sahaliang’s horse archers galloped across the Japanese front line, firing arrow after arrow upon the musketeers and yard ashigaru. However, the Japanese were able to fire back effectively and Amur horse archers in reserve swung around the infantry to retaliate. Soon, Sahaliang’s horsemen retreated through gaps in the Jin-Joseon infantry and the battle transitioned to a standard infantry slog in the center. Meanwhile, the wings of both armies had made contact as well, both light and heavy cavalry on both sides engaging fiercely. Over time, the Joseonite and Jin wings benefited from their greater size and began to push back the Amur-Japanese cavalry. Numerical superiority did not make the difference in the middle, where the better training and greater experience of the Japanese musketeers helped them hold their ground. Additionally, the yari ashigaru were better able to defend the Japanese frontline against the Jin-Joseon musketeer and swordsman formation. Soon,the Jin-Joseon infantry formation began to break, only to be saved by Gutai’s rallying of the reserves and the Joseon horse archers that had retreated. At the same time, the Jin left finally broke through their foe and despite Amur Jurchen reserves joining the fight against them, the former seemed poised to stampede upon the main Amur-Japanese camp.
It was at this moment that Gutai made a hasty decision and chose to retreat upon seeing the state the infantry was in, using the horse archers as cover. Upon receiving the orders, Shin Ryu also withdrew the Joseon cavalry from the battlefield. However, Gutai’s cavalry on the left continued to fight and nearly killed Bahai and Nagaaki. With the rest of the Amur-Japanese army gathering around their position, however, Sooge realized what was happening and finally retreated. The day finally ended at a significant cost. The Jin-Joseon army had lost 6,000 men while the Amur-Japanese army had lost 4,500. Meanwhile, at the smaller engagement, Mingginu had repelled Ebilun, forcing the Jin army back northwards.
After the battle, Gutai and his army retreated back south while Alchuka Hoton fell on August 23rd. Despite the victory, however, the Amur-Japanese army had suffered heavy losses and emerged exhausted. While Bahai consolidated his position around the fortress, Nagaaki and the Japanese retreated eastwards, recapturing Jixi in the process. In his absence, Moritora and Jin-Joseon forces clashed in what ended in a Japanese victory and a successful defense of Kuromatsu Castle. The Tiger of the North would set his sights on occupied parts of the Amur river valley and the far northern steppes that were largely now under Jin control. The approaching winter would delay his plans, though, and this coincided with a brief break of the fighting due to weather conditions and the exhaustion of men on both sides. One takeaway from the Battle of Alchuka Plains as well as from the naval warfare was that the war was increasingly costly for both sides, influencing some minds to begin considering a negotiated peace.
[1]: TTL’s and OTL’s ancient name for Lake Khanka
[2]: Jurchen name of the Acheng District of Harbin
[3]: Kaga Nagaaki’s army included 3,000 Amur Jurchens amongst its ranks.