Tag: Fukushima history

Kings in the North, Part 2

This is the 50th post on this blog. Well done for getting this far.

In 1565, Date Harumune retired and handed control of the clan over to his son Terumune. Despite this, Harumune held onto the real power, and it wasn’t until 1570, when Terumune accused several of his father’s supporters of treason and had them removed, that he gained actual power.

Date Terumune

Despite this, Terumune continued most of his father’s policies, especially in diplomacy. The alliance with the Ashina Clan was maintained, and Date diplomats reached out to the Hojo, Oda, and Shibata Clans, establishing friendly relations with several of Japan’s most powerful warlords. The Sengoku in Sengoku Jidai literally means ‘country at war’; however, alongside his diplomatic efforts, Terumune showed he wasn’t afraid to throw his weight around if an opportunity presented itself.

In 1578, the death of Uesugi Kenshin presented just such an opportunity, and Terumune dispatched forces to intervene in the internal struggle that followed. The Date intervention was ultimately unsuccessful, largely due to the military skills of the Shibata Clan, vassals of the Uesugi, who fought off the Date in several engagements.

Frustrated, Terumune withdrew, but the Shibata had apparently expected more generous rewards for their service, and in 1581, when it was clear that they would not beforthcoming, the Shibata rebelled. Terumune dispatched his army once again, this time in support of the Shibata, and the conflict within the Uesugi Clan would drag on for years.

Shibata Shigeie, one of the Shibata brothers who gave the Date so much trouble.
_^さどこ – _{^{http://blog.livedoor.jp/sadosado_4hi/archives/8412806.html, CC 表示-継承 4.0, https://commons.wikimedia.org/w/index.php?curid=99877267による}}

Closer to home, the long war against the nearby Soma Clan continued into Terumune’s reign. The Soma were based in southern Mutsu Province (the area of modern Fukushima Prefecture) and had proven to be tenacious opponents of the Date, with neither side ever able to establish a permanent advantage over the other, despite decades of conflict.

In the period of 1582-84, however, the Date finally managed to overcome the Soma. Although the latter clan was not completely subdued, the strategic situation compelled them to make peace in 1584, with the border between the two clans agreed upon by treaty.

Also in 1584, the long-time allies of the Date, the Ashina Clan, fell prey to an internal power struggle, after their lord, Moritaka, was murdered by a retainer (the official reason is said to be ‘due to sodomy’, so make of that what you will). The new head of the clan was just a month old, and so the Ashina were effectively subordinate to the Date, despite nominally remaining independent.

Shortly after this, Terumune retired, handing leadership over to his son, Masamune. Sources disagree on the exact reason for this, with some suggesting that Terumune planned to make his second son head of the Ashina, only to encounter serious opposition from within the Ashina and his own clan, who then forced him to abandon the idea and retire in disgrace. Other sources say that Terumune learned a lesson from the fate of the Ashina and decided to hand over the leadership of the Date to his son while he was still alive, rather than leave the succession to chance.

Date Masamune

Regardless of the reason, Masamune became head of the clan in 1585, and immediately set out to prove that he was not going to do things the same way as his father had. Whilst Terumune had intended to continue the war against the Uesugi, along with his Ashina and Mogami allies, Masamune made peace, without consulting either clan, leading to a sudden and serious decline in relations.

Masamune would definitively end the alliance shortly afterwards when he invaded Ashina territory, which the Ashina, unsurprisingly, interpreted as a hostile act. The invasion would prove to be a back-and-forth affair, with the Ashina successfully repelling the Date’s first attacks only to be defeated by a second wave, led by Masamune himself.

In late 1585, the Ashina asked for a truce, and a peace was mediated by Terumune and his uncle, Sanemoto. The negotiations would prove to be a ruse, however, as Ashina forces kidnapped Terumune at sword point and tried to escape back to their own territory. What happened next is a matter of debate; some sources state that Terumune, seeing that he couldn’t escape, ordered the pursuing Date forces (his own men) to open fire with their bows, killing the entire party, including Terumune.

Another source suggests that the Ashina, trapped by the Date pursuit, killed Terumune themselves, and were then cut down. A third source (written later) states that Masamune himself was responsible for Terumune’s death, and may have orchestrated the whole thing to get rid of his father. Though the exact circumstances will never be known, Terumune’s death also signalled the end of serious attempts to end the local conflicts through negotiation.

Shortly after his father’s somewhat controversial death, Masamune continued the war. In January 1586, he laid siege to Nihonmatsu Castle (in the city of the same name, in modern Fukushima). At this time, an army led by the Satake Clan, from Hitachi province (to the south), arrived to relieve the castle. The Date were defeated at the Battle of Hitotori Bridge, and Masamune himself was badly wounded before a rearguard action allowed him to escape.

The restored Nihonmastu Castle.
_{^{baku13 – 投稿者自身による著作物, CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=11354374による}}

The defeat was evidently not serious, because only a few months later, after the Satake had withdrawn, Masamune tried again, once again besieging Nihonmatsu Castle, forcing its surrender in July. Not long after this, he negotiated a peace with the Satake with the intention of focusing his efforts on finishing off the Ashina. This peace was short-lived, even by the standards of the day, as a succession crisis within the Ashina Clan drew the attention of the Satake, who supported a rival candidate to Masamune’s preferred choice.

Masamune interpreted this as the Satake intending to bring the Ashina under their control, which would have put the Date in an extremely vulnerable situation. In response, he declared his intention to wage a full-scale war against both the Ashina and Satake. In 1587, Toyotomi Hideyoshi, by now acting as regent, issued an order that all private wars should halt, an order that Masamune, for now at least, ignored.

Masamune initially had reason to regret his continued belligerence. In 1588, his old enemies, the Mogami Clan, took advantage of Masamune being distracted elsewhere and invaded Date territory at the same time as the Ashina Clan attacked in the south. After defeats at the Battle of Osaki and then at Koriyama, Masamune was obliged to seek peace with both clans, stabilising the situation in the short term.

In 1589, the peace with the Ashina Clan broke down once again, with Masamune invading the Aizu region (in the west of modern Fukushima). Masamune won a decisive victory at the Battle of Suriagehara in July 1589, causing the Ashina to flee their home castle at Kurokawa (modern Aizuwakamatsu) and seek help from the Satake. The Satake were obeying Hideyoshi’s peace order, however, and no help was forthcoming. Shortly after this, Masamune moved his base to Kurokawa Castle, and when a second order from Hideyoshi arrived, threatening direct intervention, Masamune took the opportunity to make peace.

Fukushima Prefecture, where Aizu is located.

A year later, Hideyoshi ordered the Date to join him in his attack on the Hojo Clan at the siege of Odawara. This put Masamune in a difficult spot, since the rule of his father, Terumune, the Date and Hojo had been nominal allies, and when Hideyoshi’s order arrived, it wasn’t immediately clear which side Masamune would join. Masamune eventually marched in support of Hideyoshi, but the regent wouldn’t forget Date disobedience of his peace order.

Sources
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E6%94%BF%E5%AE%97
https://ja.wikipedia.org/wiki/%E8%B1%8A%E8%87%A3%E7%A7%80%E6%AC%A1
https://ja.wikipedia.org/wiki/%E6%91%BA%E4%B8%8A%E5%8E%9F%E3%81%AE%E6%88%A6%E3%81%84
https://ja.wikipedia.org/wiki/%E8%8B%A5%E6%9D%BE%E5%9F%8E
https://ja.wikipedia.org/wiki/%E4%BA%8C%E6%9C%AC%E6%9D%BE%E5%9F%8E
https://ja.wikipedia.org/wiki/%E4%BD%90%E7%AB%B9%E6%B0%8F
https://en.wikipedia.org/wiki/Hitachi_Province
https://en.wikipedia.org/wiki/Aizu
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E6%B0%8F
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E8%BC%9D%E5%AE%97

December 19, 2025
Kings in the North

Just a quick note: Date is pronounced “Da-Tay”.

The mon of the Date Clan.

Like many of the great clans of the Sengoku period, the Date’s exact origins are subject to a fair amount of mythologising. The family originally claimed to be descended from the prestigious Fujiwara Clan, but that doesn’t have very much supporting evidence, and most modern scholars agree that the clan’s origins were far more humble.

That isn’t to say they didn’t earn their place, however. The first attested ancestor of the Clan was Date Tomomune, who was rewarded for services in battle with the manor of Date in modern Fukushima Prefecture. Tomomune himself is a bit of a murky figure (as they all seem to be), and there are still unanswered questions about his origins and even his identity, but for the sake of simplicity, we’ll agree with the Date’s own genealogy and start the story of the clan with him.

Similar to many other clans in the period, the Date were not tied down to a single geographic location, and branches of the clan would pop up all over Japan as their fortunes rose and fell. For our purposes, it is the Date clan of Mutsu Province that we’ll be focusing on.

Mutsu Province.
_{^{By Ash_Crow – Own work, based on Image: Provinces of Japan.svg, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=1690724}}

The Date largely supported the Kamakura Shogunate, founded by Minamoto no Yoritomo, and in the 13th century, the Lord of the Date is said to have been living in Kamakura (the political capital). However, when the Shogunate was overthrown, the Date threw in their lot with the Emperor and would continue to support the Imperial throne even after the establishment of the Ashikaga Shogunate in 1336.

This support would backfire, however, as the Date, in support of the Southern Court, were defeated by forces of the Northern Court, loyal to the new Ashikaga Shoguns, and ultimately obliged to switch sides. Beginning in the 1380s, the Date would set about restoring their strength by attacking rival clans in their home region. As was common at the time, these local conflicts were framed as part of the larger Northern-Southern Conflict (the Nanboku-cho Period), but were, in reality, private wars that the central authorities were powerless to direct.

Later, when the power of the Ashikaga Shoguns was beginning to fracture, the Date would use the conflict between the government in Kyoto and the Kamakura kubo to further enhance their own power. Though nominally under the jurisdiction of Kamakura, the Date would appeal directly to Kyoto to serve as their vassals. The Shogunate agreed, and when open conflict between Kyoto and Kamakura broke out in the 1480s, the Date were in a prime position to take advantage.

The territories under the nominal jurisdiction of the Kamakura Kubo.

An example of how strong the Date had become can be found in records from 1483, in which the Lord of the Date dispatched gifts to the court in Kyoto, including 23 swords, 95 horses, 380 ryo of gold dust, and 57,000 coins. This was an extraordinary fortune at the time, and seems to have led to the acceptance by the court of the Date’s position of the strongest (or at least richest) clan in the North.

Despite their wealth and power, the Date were not the most prestigious clan in the region. That honour went to the Osaki, who were faithful to the Shogunate in Kyoto and were long established. As was common during the later 15th century, however, the Osaki had a prestigious name, but their actual power was crumbling. Though nominally their subordinates, the Date would intervene in a power struggle within the Osaki Clan in 1488, bringing an end to the conflict, but effectively reducing the Osaki to vassal status in the process.

Another rival to the Date was the Mogami Clan from neighbouring Dewa Province. The clans would clash repeatedly, but in 1514, Date Tanemune would inflict a decisive defeat on the Mogami at Hasedo Castle. Shortly after this, he would marry his sister to the defeated Lord of the Mogami, effectively binding the two clans together. This would prove unpopular with the remaining Mogami vassals, and when their Lord died in 1520, and the Date attempted to take direct control, they rebelled.

The site of Hasedo Castle as it appears today.
_{^{Koda6029 – 投稿者自身による著作物, CC 表示-継承 4.0, https://commons.wikimedia.org/w/index.php?curid=124663430による}}

In defeating the rebellion, Tanemune was able to establish Date control over most of eastern Dewa Province, further expanding his clan’s power and prestige. In recognition of this, in 1522, the Shogunate appointed Tanemune shugo (governor) of Mutsu Province (the Date’s home province, remember). Tanemune was not satisfied, however, as he had apparently sought the title of tandai.

The exact distinction between shugo and tandai is a little unclear, as the titles often overlapped, but essentially, a shugo was the governor of a single province, whereas a tandai was the Shogun’s representative over a wider area. Although the power and prestige of the Shogunate were at a low ebb by this point, the fact remained that tandai was a more prestigious title, and the Shogunate’s refusal to bestow it on Tanemune was seen as a proverbial slap to the face.

Tanemune responded to this but charting his own course, although the snub is probably just a convenient excuse for what he was going to do anyway; by the early 16th century, Shogunate power was really more of a concept, and the Date were one of many powerful clans who realised that they could largely do as they pleased.

Date Tanemune.

Over the next 20 years, Tanemune would work to consolidate his clan’s control over the North, further absorbing the Osaki and Mogami clans, as well as extending physical control over most of Mutsu and Dewa Provinces. Despite his successes, all was not well within the clan; Tanemune was in conflict with his eldest son, Harumune. The exact nature of the conflict is complicated, but it got so bad that in June 1542, Harumune ambushed his father whilst the latter was out hunting, imprisoning him in a nearby castle from which Tanemune swiftly escaped (or was rescued, depending on the source)

What followed was a six-year conflict which saw the Date severely weakened, and several of their recently conquered vassals breaking free, including the Osaki and the Mogami. Eventually, the mediation of the Shogun brought about an official peace, but in reality, the feud didn’t end, and although Harumune would take his place as the de facto head of the clan, Tanemune, despite becoming a monk, remained an enormously influential figure.

Harumune’s reign would be occupied with reestablishing Date power. The situation was far from ideal, however, and he was eventually forced to confirm many of the concessions that had been granted to vassals by both sides, signing away territory and privileges in exchange for obedience.

Date Harumune

One upside for Harumune was the fact that he had no fewer than eleven children, six sons and five daughters, who would be useful pawns in returning former vassals to the fold. All of his daughters were married either to powerful clans, securing alliances, or to senior vassals, ensuring their loyalty, and by the 1560s, the Date’s position was once again strong.

In 1565, Harumune retired and handed control to his son, Terumune, although, as was common, he retained all the actual power. A year later, the Ashina Clan attacked the Nikaido, who were allied with the Date through the marriage of one of Harumune’s daughters. The Date intervened but were defeated, and when the Nikaido surrendered shortly afterwards, peace between the Date and Ashina was secured through another marriage, this time between the Lord of the Ashina’s eldest son and Harumune’s fourth daughter.

Harumune apparently opposed this marriage, and in response, Terumune entered into a secret agreement with the Ashina, in which they would agree to support him in the event of an outbreak of conflict between father and son. The feud between father and son would only be resolved in 1570, when Terumune removed several retainers who had facilitated Harumune’s rule from ‘behind the curtain’. With this, the relationship seems to have improved, as Harumune was now effectively powerless anyway.

Like most of his contemporaries, Terumune’s reign would be dominated by war, but we’ll talk about that next time.

Sources
https://en.wikipedia.org/wiki/Mutsu_Province
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E6%B0%8F
https://ja.wikipedia.org/wiki/%E6%9C%80%E4%B8%8A%E6%B0%8F
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E7%A8%99%E5%AE%97
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E6%88%90%E5%AE%97
https://ja.wikipedia.org/wiki/%E5%A4%A7%E5%B4%8E%E6%B0%8F
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E5%B0%9A%E5%AE%97
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E5%AE%97%E9%81%A0
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E9%83%A1
https://ja.wikipedia.org/wiki/%E5%B8%B8%E9%99%B8%E5%85%A5%E9%81%93%E5%BF%B5%E8%A5%BF
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E6%9C%9D%E5%AE%97
https://en.wikipedia.org/wiki/Dewa_Province
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E6%99%B4%E5%AE%97
https://ja.wikipedia.org/wiki/%E4%BC%8A%E9%81%94%E8%BC%9D%E5%AE%97

December 16, 2025