The first sword we will cover in depth is the Onimaru Kunitsuna (鬼丸国綱). This sword was actually introduced in another article, entitled “Unique Swords with the Finest Edge“. Wielded by those of nobility and military status, it is portrayed as a mystical sword able to dispatch evil spirits, thus protecting its owner. Bearing such an illustrious profile, one would imagine it’s a true treasure with such power anyone would never bear to part from it. To be honest, this perception is not 100% accurate, for at a time the Onimaru Kunitsuna had a very negative reputation. Before we go into its rather rocky history, let’s examine this sword’s specifications.

- Status: Imperial treasure
- Blade length: 78.2 cm
- Curvature: 3.2 cm
- Maker: Kunitsuna
Out of the 5 swords, the Onimaru Kunitsuna is deemed a treasure of the Imperial Palace. This, however, does not mean it’s a national treasure, for it is rarely on display for public viewing, while few publishing have pictures of it. This may have to do with its rather complex history, and how it came to be included in the safekeeping of the Imperial Palace. Much of its extra-ordinary status comes from documents considered recordings of actual past events, like the novel-styled historical writings from the “Taiheiki” (太平記), and the Imperial logs of legendary and political matters from the “Gobutsu Chōsho” (御物調書). When reviewing the actual documents or sites that reference these same sources that pertain to the Onimaru Kunitsuna, you notice that much of it is unusually detailed dialogues and labeling just for a sword, which can range from its passing from one owner to another as a spoils of war, to reference during a simple evaluation by order of a government official. While I can’t say that all that’s written about the Onimaru Kunitsuna is factual or not, I will say that some of the info is a little over the top, and should be taken with a grain of salt.
BELOVED SWORD OF THE HŌJŌ CLAN
The origins of this sword is traced to around mid 1200s, during the Kamakura period. Hōjō Tokimasa, the 5th Regent who was in control of the government body known as Kamakura Bakufu, commissioned the swordsmith Awataguchi Kunitsuna to craft him a special sword. This was fulfilled, with the sword being called “Kunitsuna” based on the name signed on it.

This sword would also gain an addition to its name, “Onimaru”¹, a little later. This came about when Tokimasa was tormented by nightmares caused by a demon while sleeping. As if willed by an unknown power from his keepsake sword, Tokimasa drew Kunitsuna out of its sheath and swung it down, cleaving off a part of the leg of his light stand that had the mark of a demon on it. From this, Tokimasa would give his sword the full title “Onimaru Kunitsuna”, as he believed it was good luck against mystical danger. Thus, it was a treasure of the Hōjō family for several generations.
However, this “good luck” of the Onimaru (title choice for remainder of article) was not witnessed again outside of the Hōjō household. This beloved sword was safely in the possession of this family up until the 14th successor Hōjō Takatoki, and after his passing, would later fall into the possession of Nagoe Takaie, who was the son of Hōjō Tokiie². It is said that in 1333, as many groups rose to oppose the Kamakura Bakufu rule controlled by the Hōjō clan, a particular rivalry between the Nagoe (Hōjō) clan and Akamatsu clan erupted, leading to skirmishes between both sides. The Hojo clan made an attempt to claim Yamazaki (present-day Ōyamazaki Town, Kyoto) from the Akamatsu clan. Takaie took part in this as he rode into the fray with the Onimaru at his side at Koganawate (present day Fushimi Ward, Kyoto City)³. However, he suffered the ill fate of being shot between the eyebrows by an arrow, dropping him dead in battle. Due to this tragedy, the Onimaru would later be returned back to his father Takatoki.
MISFORTUNES AS AN IMPLEMENT FOR WAR
A war commander by the name of Nitta Yoshisada would be next to gain possession of the Onimaru. This happened during an assault on Kamakura later in the same year, where it became evident that the might of the Hōjō clan was waning. Hōjō Kunitoki made an attempt to repel the assault, but things were looking grim on his side. At this time, he would have in his possession the Onimaru, and attempted to escape. However, he was caught by a subordinate of Nitta Yoshisada, assembled with other family members at a temple called Tōshōji, and was forced to commit suicide. Here is where the beloved sword would switch to the hands to Yoshisada. To claim such a treasure from a powerful family such as the Hōjō would mean good things to come…or so that was the thought.

We turn to the Ashikaga clan, who originally were supporters of the Hōjō clan, and rose in power by establishing their own military government in Kamakura by the new shogun Ashikaga Takauji. Not in agreement of the sudden change of power, Nitta Yoshisada opposed Ashikaga Takauji, resulting in them going to war. At first nothing impactful took place between the two sides, but soon Takauji would start to get the upper hand. In 1338, during the battle at Fujishima in Echizen Province, Yoshisada rode out into battle with the Onimaru and another sword known as the “Onikiri” (鬼切), attempting to prevail through his 2 auspicious swords. However, being caught by a rain of arrows from the enemy, he was shot dead as one of the arrows pierced between his eyebrows. Yet again, another display of the Onimaru providing no protection to those who attempt to wield it in physical battle
As the spoils of war, the Onimaru, along with the Onikiri, were taken by Shiba Takatsune, a commander who was in the service of the new shogun. Learning of the successful victory over Nitta Yoshisada and his army, Takauji sent a messenger to learn the whereabouts of the swords. When questioned by the messenger, Takatsune lied that both swords were kept in a training center, but was lost in a fire that erupted inside, destroying the building and everything inside. It would later be discovered that this was a lie, which Takauji lamented over this fact. Eventually, Takauji managed to secure the auspicious sword in his possession.
An interesting observation worth noting is that from this point on, the Onimaru will not be taken to the battlefield again, due to the misfortune of defeat and death that befell those thinking its surreal spiritual power would transfer to victorious physical strength⁴. Instead, it stayed as one of many valuable treasures within the position of the Ashikaga clan.
THE VALUABLE TREASURE MANY REFUSED TO TAKE IN
From here on forward, the Onimaru will pass through the hands of other prominent figures in Japan outside of being a spoils of war. This first takes place sometime around the late 1560s to early 1570s, when the 15th Ashikaga shogun Ashikaga Yoshiaki gave potential rival Oda Nobunaga the sword as a peace offering. In turn, Nobunaga gave it years later to his vassal, Toyotomi Hideyoshi⁵. By now, the Onimaru had a reputation of being a mystical blade that can eradicate evil spirits, but bearing the potential of bringing ill luck to those who wield it out on the battlefield. Taking an interesting turn by believing in the tales of its ability to ward away evil spirits, Hideyoshi had it evaluated by the Honami clan, and lent it to Honami Kōtoku for safe keeping.
The Onimaru stayed as part of the Toyotomi family’s collection for a few decades. However, this would change after their demise when they lost during a war on their home, Ōsaka castle, by Tokugawa Ieyasu and supporters from eastern Japan in mid 1615⁶. Ieyasu would seize control over Japan as the new shogun, and establish the Tokugawa Shogunate. As if following protocol, Kōtoku would give the sword to the new Shogun, as it now has a new owner. Despite receiving this great sword, Ieyasu decided to follow suite and pass it back to Kōtoku for continued safe keeping…possible due to suspicion of its “unlucky” reputation.

In 1626, Ieyasu’s granddaughter, Tokugawa Masako, gave birth to the 2nd prince of the Imperial family, whose name was Sukehitoshinō. As she was be-wedded to Emperor Gomizunō and tied the Tokugawa family’s lineage to the Imperial line, this was an honorable occasion. As an offering, the Tokugawa family had the Onimaru delivered to the Imperial family, as a sign of their connecting with the newborn prince. Unfortunately, Sukehitoshinō would suddenly pass away in 1628, after his 3rd birthday⁷. The cause of death was thought to have been due to the “unlucky” sword, thus having it returned back to The Honami clan for safe keeping yet again.
The Onimaru remained in the care of the Honami clan for some time. They were also rewarded for their dedicated service at some point, as the sword was maintained in exceptional condition. However, after being unclaimed for a few centuries, the faith of the Onimaru would finally be decided in 1867, with rule over Japan being restored to the Imperial line after the fall of the Tokugawa Shogunate. With this change in power, the sword was no longer an item of the Tokugawa family, but instead recognized as an Imperial treasure. It would then be added into the collection of the Emperor and the Imperial Palace in 1881, after the Honami clan fell into a decline in a successor to properly fulfill the job of sword care & evaluations. This is how the extraordinary sword known as Onimaru Kunitsuna would find its last home, and remain as part of the Imperial collection to this day.
ENDING
We close this article on the 1st sword out of the Tenga Goken, Onimaru Kunitsuna. Bearing the reputation of its spiritual powers to eradicate evil spirits, it received quite a reputation during a time where many were superstitious. On the flip side, it was also deemed bad luck, which stemmed from providing no protection against physical dangers, to bringing untimely death. Are all these tales about the Onimaru Kunitsuna warrant? It’s impossible to get full clarity, but it does indeed make for an interesting tale. Stay tuned part 3, which will cover the the next sword known as Juzumaru Tsunesugu.
1) This is also the shorthand name for the sword
2) The Nagoe clan was a related branch of the Hōjō line
3) This particular clash is properly know as Koganawate no Gassen (Battle at Koganawate)
4) It is rumored that the 13th shogun Ashikaga Yoshiteru (1536~1565), a skilled swordsman, wielded the Onimaru against overwhelming odds at Nijō Gojo in Kyoto. This is a statement without a reliable source, so can’t say that this is true.
5) Toyotomi Hideyoshi is the name he’s most recognized by after he became shogun of Japan in late 1500s. While he was serving under Oda Nobunaga, he went by a different name, which was Hashiba Hideyoshi.
6) This war is known as “Ōsaka no Jin” (Siege of Ōsaka), which was a 2-part assault with the 1st taking place in the winter of 1614, then the 2nd in the summer of 1615.
7) This is based on the traditional age calculating method primarily used in Eastern Asian, where a newborn baby is considered one year old, then gets one more year added after the New Year.