Mogami Yoshiaki

Mogami Yoshiaki (最上 義光) was a daimyō of the Yamagata Domain in Dewa Province, in the late Sengoku and early Edo periods. Known as "Fox of Dewa".

His younger sister, Yoshihime, later became the wife of Date Terumune and gave birth to his eldest son, Masamune. In other words, Yoshimitsu was Date Masamune's uncle.

It was recorded in historical documents that his body height was over 180 cm.

Biography
Mogami Yoshiaki was born on the first day of the first month of the Tenbun era (1546) to Yoshimori as his father, and Nagaura as his mother, his birth name is Hakujumaru and succeeded his father as daimyō of Yamagata Prefecture. The Mogami clan which he hailed from has a prestigious bloodline that descended from the Shiba clan, a branch of Ashikaga clan, and the "Yoshi" character of his name "Yoshiaki" was bestowed by the 13th shogun, Ashikaga Yoshiteru himself. Furthermore, the Mogami clan was in the position as direct vassals of the Ashikaga shogunate. As a boy who grow from a samurai and aristocratic clan, Yoshiaki has the literary ability to compose letters over three meters long, and was able to enjoy renga in Kyoto alongside famous renga poets such as Satomura Shōha.

In June 14, 1563 (Eiroku 6), Yoshiaki and his father went to Kyoto to have an audience with Shogun Yoshiteru and present him with a horse and a sword.

In 1564, When Yoshihime (Date Masamune mother), who was his sister, married Date Terumune, the Mogami clan became allied with the Date clan. At some point during this period, the Mogami clan undergo a succession conflict.

Due to the confusion over the succession of the Mogami clan, local lords in Dewa Province, such as Tendo Yorisada, his clan members Higashine Yorichage, Kaminoyama Mitsukane, and Shiratori Nagahisa, were trying to become independent. Therefore, Yoshiaki, who inherited the family headship, used fairly forceful methods to suppress their attempt to declare independece from the Mogami clan. As for Kamiyama Mitsukane, he had his vassal Satomi Minbu betray him and kill him, and as for Higashine Yorikage, he had his vassal Satomi Kageyori betray him and kill him. Having thus destroyed the unity of his family, Yoshiaki exiled Tendo Yorisada's son Yorimizu, who had succeeded him after his death.

in 1570, at the age of 25, Yoshiaki inherited the clan leadership from his father and set upon his goal of reviving the hereditary position of his clan as Oshu Tandai (Overseer of Dewa Province, areas which encompassed modern-day area encompassing Akita and Yamagata prefectures, during the Muromachi period). He expanded into not only the northern and western parts of Yamagata Prefecture, but also southern part of Akita Prefecture.

Unification of Dewa province
In 1571, Mogami Yoshiaki officially became the head of the Mogami clan. During this time, Yoshihime wrote information about the Date clan to Yoshiaki, her and Yoshiaki's actions made the Date clan distrust the Mogami family. Yoshiaki fought against the Date clan twice in different years, 1574 and 1578, in both battles Yoshihime advanced to the middle of the battlefield to create a peace treaty. Yoshiaki married a woman from the Osaki clan of Mutsu, who was his relative. Because of this, the relationship between Yoshimitsu and Masamune Date deteriorated when his nephew Masamune Date attacked the Osaki clan.

In 1580, he get help from Satomi Minbu. Allowing him to successfully take over the Kaminoyama Castle. so Kaminoyama Mitsukane committed suicide.

In 1581, he has expanded its power to Murayama District and took over Oguni Castle. Yoshiaki also attacked Sakenobe Castle and forced Sakenobe Hidetsuna to surrender. Later, Hidetsuna became Yoshiaki's chief vassal.

In 1583, he expanded the Semboku areas, and threatened Daihōji Yoshiuji. Daihōji announced their war with the Mogami clan as result. Later, Yoshiuji was defeated and committed suicide.

In 1584, Yoshiaki then attacked the Sagae clan which led by Sagae Takamoto committed suicide. Yoshiaki then attacked the Tendo clan, who were based in Tendo, just north of Yamagata, into Kokubu (present-day Miyagi Prefecture), led by Tendō Yorizumi. Later, Yorizumi fled to the territory of Kokubun Morishige, causing the Tendō clan to collapse. Furthermore, he also defeated the Shiratori clan within the same area. Meanwhile, in Dewa Province, one of the remaining local lords who was in conflict with Yoshiaki was Nagahisa Shiratori. Nagahisa Shiratori's territory was in Murayama County, Dewa Province, near present-day Murayama City. He was an obstacle to Yoshiaki, who was trying to pacify Dewa, but he also had connections with Oda Nobunaga and was plotting to obtain the title of Dewa no Kami (Lord of Dewa). Yoshiaki, who had read of these developments, invited Shiratori Nagahisa to his castle, Yamagata Castle, in 1584, claiming to be seriously ill. According to the "Tale of Mogami Yoshiaki" written in the early Edo period, Yoshiaki, who was bedridden, asked Shiratori Nagahisa to "serve as guardian until my eldest son, Yoshiyasu, comes of age," and handed him a family tree that had been passed down from his ancestors. It is recorded that when Shiratori Nagahisa about to receive the family tree document, Yoshiaki suddenly killed him with a sword that he had hidden. With the elimination of Nagahisa, the Mogami clan finally asserted their dominance of the region. It was reported that the assassination of Nagahisa was ordered by Oda Nobunaga several years prior before the Honnō-ji Incident in 1582, since Nobunaga saw Nagahisa has committed a crime that inccured his wrath, which was lying to Nobunaga by claiming that he is the ruler of Dewa province.

In 1586, Yoshiaki fight against Onodera Yoshimichi. Yoshiaki's eldest son, Mogami Yoshiyasu and Tateoka Mitsushige succeeded in defeating the Onodera reinforcements. On October, Yoshiaki crossed the Rokuji Highway and invaded Shōnai in an effort to reinforce Tōzenji Yoshinaga, lord of Tozenji Castle, from the attack of his enemy, Daihōji Yoshioki. In the end of this conflict, Yoshioki was defeated in a battle on the same month and commited suicide, causing the Daihōji clan extinct.

In 1587, he defeated the Daihōji clan, the leader of the Shonai region (western Yamagata prefecture), and succeeded in taking control of Shonai. However, his nephew, Date Masamune, also expanding his own ambition at the same time, and he was targetting the domains within the Mogami clan.

In 1588, an internal conflict broke out within the Osaki clan, the former Oshu Tandai, protector of Oshu region, with the Mogami and Date clans, who had each requested reinforcements, entered into a state of war. This conflict was brought to a peace agreement through the desperate pleas of his younger sister, Yoshihime, but while they were distracted by the conflict with the Date clan, Honjo Shigenaga, a subordinate of the Uesugi clan from Echigo Province, took over Shonai. In response to this, Yoshiaki sought to recapture the region from the Uesugi clan. However, when Toyotomi Hideyoshi came to power In 1590, he forbade any private wars among daimyo or feudal lords in Japan. Yoshiaki then submitted to Hideyoshi authority. In the same year, Yoshiaki was given about 200,000 koku by Toyotomi Hideyoshi.

In 1589, on May, Tokugawa Ieyasu sent a letter to Katakura Kagetsuna, imploring him so Date Masamune reconcile with Yoshiaki.

In 1590, after the Siege of Odawara and participated in attacking Kunohe Rebellion. During this time, Toyotomi Hidetsugu, who was chosen as Toyotomi Hideyoshi's successor, fell in love with Yoshiaki's daughter, Princess Koma, and married her, and Yoshiaki became an important Toyotomi daimyo as he related with the Toyotomi clan. In 1591, Yoshiaki was allowed to use the surname of Toyotomi, and usually called himself Hashiba Yoshiaki. Although he did not end up sailing to Korea during the Bunroku Invasion, in 1592, he went to Nagoya Castle in Hizen with 500 of his retainers to prepare for the passage to Korea.

In July 1595, an incident occurred which involving his daughter who has been bethroted to Hidetsugu. This incident was triggered by the birth of Hideyori to Hideyoshi's beloved Yodo-dono. This caused Hidetsugu accused of alleged treason and committed seppuku at Mount Kōya on the order of Hideyoshi, presumably to secure the inheritance of Hideyori. The aftermath of this incident affected Not only Hidetsugu, but also his wife, concubines, and children were also executed at Sanjogawara. Yoshiaki's daughter, Komahime, who was only 15 years old and had recently married Hidetsugu, was also executed in result. Yoshiaki begged for her life but was refused. Komahime was beheaded along with Hidetsugu's other wives and concubines, and her body was dumped in the Sanjogawara River on August 2 of the same year. Furthermore, Yoshiaki was also suspected of participating in the rebellion of Hidetsugu, but was pardoned with the assistance of Tokugawa Ieyasu's intercession on his behalf. However, as result of the execution of Komahime, Yoshiaki's wife, Osaki-dono, also struck with deep grief by the sudden death of her daughter and passed away on August 16. After this incident, Yoshiaki grew closer to Ieyasu and became his strongest supporter.

In 1597 Yoshiaki's son Yoshiyasu was eventually given the official title of Shūri-daifū title as the eldest son of the Mogami family.

Sekigahara war
In 1600, when the Sekigahara war broke out between Ieyasu against his enemies led by Ishida Mitsunari, Ieyasu entrusted Yoshiaki as commander-in-chief of the northern Oshu. On April 19, Ieyasu instructed the Nanbu clan, Onodera clan, and Akita clan to obey Yoshiaki's command, after Ieyasu turn back his army to face Mitsunari's forces on July 25, while he was at Oyama (Oyama City, Tochigi Prefecture). Yoshiaki was also informed by Ieyasu that the campaign against the Uesugi clan was cancelled. As a result, the troops that had gathered in Oshu returned to their home provinces. The Uesugi clan became more emboldened and began to actively work against Ieyasu, contacting Yoshiaki and others to encourage them to join the Uesugi side. Yoshiaki was in a big trouble. He still supported Ieyasu, but if he did not join the Toyotomi side, there was a high possibility that he would be attacked by the Uesugi. As Yoshiaki believed in Ieyasu's victory in the Kamigata region, they tried to buy time, but in the end, the Uesugi forces invaded the Mogami territory on September 8. Yoshimichi Onodera, who was based in Yokote Castle (present-day Yokote City, Akita Prefecture), also responded to Uesugi and invaded the Mogami territory. This resulted with now the Mogami clan withstand the invasion of battled Uesugi Kagekatsu.

The Uesugi forces, numbering more than 20,000, were invaded from the south by the main force commanded by Naoe Kanetsugu via the Kitsunegoe Highway, and from the west by the Shonai area. Because the difference in military strength between the Mogami force the Uesugi forces were huge, Yoshiaki requested reinforcements from Date Masamune, which message relayed through Yoshiaki's eldest son, Yoshiyasu, Masamune decided to send reinforcements out of obligation for his mother, Yoshihime, who also happen to a sister of Yoshiaki, and also loyalty to Ieyasu. In the same campaign, Yoshiaki aided in Date's siege of Shiroishi, and was then attacked in his own home castle of Hataya and Kaminoyama. He used geographical advantages to resist the invasions. Yoshiaki concentrated his forces in Hasedō Castle, Yamagata Castle, and Kaminoyama Castle. Naoe Kanetsugu's forces launched an all-out attack on Hasedō Castle, which was defended by 1,000 men. with the cooperation of the reinforcements sent by Yoshiaki from Yamagata Castle and the soldiers of Hasedō Castle, and their high fighting spirit, the defenders of Hasedō Castle fought well. Based on the estimation by team from Mogami Yoshimitsu History Museum research on the battle ground sites along with Uesugi clan's estimated route, and the estimation of both forces' composition, Hasedō Castle should be fallen easily. However, it was concluded that the guerilla warfares conducted by Yoshiaki to harass the route of the Uesugi army played role in the successful defense of the castle. The Uesugi forces were defeated in the attack on Kaminoyama Castle, and fled back to Yonezawa in disarray. It was said that at one occasion, a group of Mogami clan's ninja infiltrated the camp of Naoe Kanetsugu, stealing his battle standart, which later hoisted on the Hasedō Castle's gate, which demoralized the Uesugi troops greatly in effect. In the 15 days of ineffective siege against the Hasedō Castle, the Uesugi troops cannot capture it from the persistent Mogami forces. In the final phase of this siege, the Uesugi forces launched another all-out attack on Hasedō Castle, but with the help of Date's reinforcements, they were able to hold out against the large Uesugi forces. In the end, when information came in that Tokugawa Ieyasu emerged victorious in the main Sekigahara battle, The uesugi forces under Kanetsugu began to withdraw from Hasedō Castle. Switching positions, Yoshiaki began to pursue them, but Kanetsugu himself concentrated his riflemen to defend his retreating army, and managed to withdraw safely back to Yonezawa.

In 1601, Yoshiaki also progressively recaptured the district of Tagawa, Kushibiki, and Yusa from the Uesugi clan. After the campaign ended, which the Mogami clan was rewarded with their domain increase from 200,000 to 570,000 koku in return for his loyalty for the Eastern army during the war. This made the Yamagata domain the fifth largest in Japan at the time, excluding the land held by Tokugawa. On May 11, Ieyasu, who had established his hegemony over the Toyotomi government, visited the Imperial Palace to receive an audience with the Emperor. He was accompanied by Mori Tadamasa, who had been instrumental in the attack on the Sanada clan, and Ii Naomasa, who had led the vanguard in the Battle of Sekigahara, as well as Mogami Yoshiaki and Oda Nagamasu.

Edo Period
After the Tokugawa shogunate in Edo was established, Yoshiaki became the first ruler of the Yamagata Domain and implemented various policies. One of these was the establishment of a provincial law called the "Mogami Family Law".

During this era, Yoshiaki also attempted many construction projects such as restoring temples and shrines, including all the old temples in the Mogami clan domains that had existed since ancient times. The five-story pagoda at Mount Haguro, a national treasure, was also repaired by Yoshiaki. Furthermore, he also made great efforts in improving water transportation on the Mogami River. There were three difficult spots along the Mogami River, but he improved them to facilitate shipping between Kyoto and Yamagata. He also constructed a massive irrigation system (called Kitadate Ozeki) in Shonai, with a total length of over 30 kilometers, and created 4,200 hectares of vast rice fields. He also followed the advice of his vassal Kitadate Toshinaga, to overrode opposition from those around him and gave permission for those construction, providing financial and material support to ensure its success.

It was noted that the Yamagata Castle is notable for not having a castle tower, despite being the second largest castle north of the Kanto region after Edo Castle. According to the record "Ugenki," despite the pressure from Mogami senior vassals who urged to build a castle tower, Yoshiaki refused to allow it, as he did not want to overwork the citizens of his territory just to built castle towers.

However, after this, the relationship between Yoshiaki and his eldest son Yoshiyasu deteriorated due to a power struggle between their respective vassals. As the conflict be continued, Yoshiaki worried that this could led to a civil war which potentially caused the shogunate to strip the Mogami clan's control of their regions. Therefore, he decided to pass on the family headship to his second son, Iechika. It was believed the decision also due to factor that Tokugawa Ieyasu had fondness with Iechika, as Ieyasu had given Iechika name from the character of his own name, and he was well remembered by Ieyasu. Besided during that time, Iechika was under the service of Ieyasu's son, Tokugawa Hidetada. Yoshiaki thought that if he allowed Iechika to succeed him as head of the family, he would be able to avoid the Mogami clan being punished by the shogun. In 1605, Yoshiaki ordered Yoshiyasu to enter Mount Koya and become a monk. Yoshiyasu followed his father's orders and set off for Mount Koya, but was murdered by one of Yoshiaki's retainers on the way. It is not known whether Yoshimitsu ordered Yoshiyasu's assassination. However, after the assassination, Yoshiaki made Jonenji Temple under Yamagata Castle his family temple in order to pray for Yoshiyasu's soul.

Death
He died from illness at Yamagata Castle in 1614 at the age of 68. Yamagata maintains the Mogami Yoshiaki Historical Museum, just outside the rebuilt Great Eastern Gate of Yamagata Castle, which displays his helmet, battle command baton and other implements he actually used.

It was reported that during his reign as Mogami clan's head, there is no single local uprising that occurred within the territories of Mogami clan.

Legacy
Mogami Yoshiaki laid out and built the castle town, which became the foundation of modern-day Yamagata City. He controlled the "Three Difficult Places" on the Mogami River, making navigation safer from the Sea of Japan to the inland, and bringing the culture of Kyōto and Ōsaka to Yamagata. His dam building projects at Kitadaseki, Inabazeki and other places, and other irrigation control measures helped develop rice cultivation in the Shōnai plain.

A museum named after Mogami Yoshiaki, who built the foundations of Yamagata city, was built by the officials of Yamagata City on December 1, 1989, to collect, preserve and study all the materials related to the Mogami clan which ruled the city from the Azuchi–Momoyama period until early Edo period.

Notable vassals

 * Tateoka Mitsushige
 * Sakenobe Hidetsuna
 * Eguchi Gohei
 * Satomi Minbu
 * Ujiie Sadanao
 * Ujiie Munemori
 * Shimura Akiyasu