Role of the Sword Futsunomitama-no-tsurugi in the Origin of the Japanese Bushidō Tradition

One of the formative narratives in Japanese martial arts is the bestowal of the mystical sword Futsunomitama-no-tsurugi upon Emperor Jinmu, the legendary founder of Japan. Within the Kashima Shinden Bujutsu lineage, this bestowal is attested as a critical event in the initiation of the principles of bushidō martiality. However, the practical reasons for its signicance have been unclear. Drawing on historical and archaeological records, in this paper we hypothesise that the physical conformation of the legendary sword Futsunomitama-no-tsurugi represented a comparatively incremental progression from the one-handed short swords imported from mainland Asia. ese modications allowed for a new, two-handed style of swordsmanship, and therefore it was the combination of the physical conformation of Futsunomitama-no-tsurugi and the development of appropriate techniques for wielding it that formed the basis of the martial signicance of the “Law of Futsu-no-mitama”. We also argue that this new tradition of swordsmanship was the nucleus around which the Kashima Shinden Bujutsu lineage would develop, and therefore represented a critical rst step towards the later concepts of bushidō. We also present a working model of what the techniques for usage of Futsunomitama-no-tsurugi might have been, and provide an account of an experiment testing its application.


Izvleček
Ena od temeljnih pripovedi v kontekstu japonskih borilnih veščin je podelitev mističnega meča Futsunomitama-no-tsurugi cesarju Jinmuju, legendarnemu ustanovitelju Japonske.V tradiciji Kashima Shinden Bujutsu je ta podelitev pomemben dogodek na poti do uresničevanja načel bushidōja.A njegov velik pomen ni bil nikoli v resnici pojasnjen.Upoštevajoč zgodovinske in arheološke zapise v tem članku podajamo hipotezo, da je One of the formative narratives in Japanese martial arts is the bestowal of the mystical sword Futsunomitama-no-tsurugi upon Emperor Jinmu, the legendary founder of Japan.Within the Kashima Shinden Bujutsu lineage, this bestowal is attested as a critical event in the initiation of the principles of bushidō martiality.What is unclear, however, is just why this was a pivotal event.If the story of Futsunomitama-no-tsurugi is intended to capture a military innovation, then it should consist both of a technological improvement or re nement, and of a change in strategic or tactical thinking that enabled full use of the new technology.Given that the evolution of weapon design in the Japanese archaeological records is a well-developed eld, and that there are no major theories arising as to the nature of Futsunomitama-no-tsurugi, our hypothesis is that the story has its roots in at most a modest re nement of military technology, and thus must have been mostly a revolution in tactics or strategy.at being the case, insight into the nature of that re nement may be sought in the curriculum and history of the martial lineages which associate themselves with the mythology of Futsunomitama-no-tsurugi.
In this paper, we explore this hypothesis in two parts.In the rst, using archaeological and historical records, we compare a sword design linked to the Futsunomitama-no-tsurugi narrative with other contemporary sword designs.Based on this, we argue that the con rmation of a physical manifestation of Futsunomitama-no-tsurugi would have been an incremental progression towards a longer sword more suitable for two-handed use, with a change in curvature towards an uchizori design.
To make the case that these changes were signi cant beyond an aesthetic sense, in the second part we develop the idea that the corresponding tactical revolution was a new tradition of swordsmanship, which became the nucleus around which the Kashima Shinden Bujutsu lineage would develop.By analysing the traditions and kabala of the Kashima Shinryū, we can then present a working model of what the techniques for usage of Futsunomitama-no-tsurugi might have been, and provide an account of an experiment testing its application.

Futsunomitama-no-tsurugi
e Kashima Shinden Bujutsu are those martial traditions that date their origin back to Kashima-no-Tachi, the martial art revealed by the deity Takemikazuchi-no-mikoto to Kuninazu-no-Mahito, the head priest of the Kashima Grand Shrine during the fth century (Seki 2009).e lore of the Kashima Shinden Bujutsu states that it realises its divine nature by virtue of being derived from the "Law of Futsunomitama".Meanwhile, the Futsunomitama-no-tsurugi (sometimes translated as the "cross sword") is a divine sword described in both the Kojiki (1963) and the Nihon Shoki (Kuroita 1943).ey recount (e.g., the description in the Kojiki; Fig. 1) that its origins arose during the Eastern Expedition of Kamuyamato iwarehiko-no-mikoto (the name of Emperor Jinmu before taking the throne; Fig. 2), when according to those accounts he fell into trouble at Kumano in 663 BC (Urabe Kanenaga, transcribed 1522).At this point, Amaterasu-ōmikami (Fig. 3) and Takami-musubi-no-kami (the divine ancestors of the Imperial family) dispatched Takemikazuchi-no-mikoto to rescue him.Upon considering the situation, Takemikazuchi-no-mikoto judged that the Imperial progenitor's mission of the paci cation of the nation could be achieved simply by depositing Futsunomitama-no-tsurugi in the treasury of one Takakuraji (the progenitor of the Mononobe clan, or Weapons Ministry of the Imperial Court), and then allowing Takakuraji to pass it on to Kamuyamato iwarehiko-no-mikoto.
e Sendaikujihongi (Urabe 1522), the historical records of the Mononobe clan, expands further on the circumstances.It recounts that the army led by Kamuyamato iwarehiko-no-mikoto had attacked and subdued the Nishikitobe clan, who had been ruling the entirety of the coastal region around Arasakatsu in Kumano, at which point the Earthly Deities (who opposed the conquest of the land by the imperial progenitors) spread a "poisonous vapour" which caused all of the Imperial Army to lose their ghting spirit.In the Kojiki, this loss of ghting spirit is described using the character 惑, meaning "beguiling" or "perplexing".In the natural order of things, having defeated the armies of the Nishikitobe clan, the Imperial Army should have been in high spirits.However, the Nihon Shoki similarly documents this poisonous vapour sapping the martial spirit of the entire army, and it is not implausible to interpret these "poisonous vapours" as being wild and baseless rumours aimed at shaking the spirit of the army.As outlined above, Takemikazuchi-no-mikoto's response to this was to deliver Futsunomitama-no-tsurugi to Kamuyamato iwarehiko-no-mikoto, with Takakuraji as the agent.According to the Sendaikujihongi, as the sword Futsunomitama-no-tsurugi was both symbol of the legitimacy of the August Deity's army and evidence of advanced military technology, the Imperial Army regained its martial spirit and willingness to ght.For this, the sword Futsunomitama-no-tsurugi was recognised as a "sword with the power to pacify the angry deities" upon the commencement of Emperor Jinmu's reign.Yet there are no records that identify exactly what property of Futsunomitama-no-tsurugi made it such a powerful, advanced weapon technology for those times.
Later, in the reign of the Emperor Sujin, Futsunomitama-no-tsurugi the sword was enshrined as a deity itself (Futsunomitama-no-ōkami) at Isonokami Shrine.In 1874, Kan Masatomo, the head priest of the Isonokami Shrine at that time, was granted permission to conduct an excavation in the kinsoku-chi (forbidden area) behind the front shrine, and found a sword buried there (Fig. 4).In a report dated August 24th 1874, to Shishido Tamaki, a deputy minister of the Ministry for Religious Education, Kan described the form of the sword found in the shrine as an uchizori (inward-curving) ring-pommelled iron sword, with an overall length of 84.55 cm, a blade length of 66.18 cm, a width of 3.64 cm, an inner curvature of 1.21-15.2cm, a hilt length of 12.73 cm, and a pommel diameter of 3.64 cm.
According to this report (Ueda and Saeki 1989), the sword was archaeologically determined to date sometime between the Yayoi and Kofun periods (between the 4th century BC and the 3rd century AD).It is therefore plausible to assume that this sword, if not the historical Futsunomitama-no-tsurugi itself, is based on its form.We can thus compare the properties of this Futsunomitama-no-tsurugi to those of other contemporary swords, to try and identify the characteristics that set it above its rivals.
Incidentally, much later in 622 AD, Fujiwara-no-Kamatari (the founder of the Fujiwara or Kuninazu clan, with the familial deity of Amenokoyane-no-mikoto) decapitated Soga-no-Iruka using a short uchizori sword of almost the same shape as Futsunomitama-no-tsurugi as part of the Isshi Incident (Fig. 5).e demands of propriety would have forced Fujiwara-no-Kamatari to carefully choose a weapon that would demonstrate respect for Soga-no-Iruka, who was his superior at court, and this emphasises that Futsunomitama-no-tsurugi remained a weapon with divine and mystical associations at this time.e incident is credited as the trigger of the Taika Reform conducted by Naka-no-ōe-no-Ōji (the name of Emperor Tenchi before enthronement) and Fujiwara-no-Kamatari.
From what is known of the di usion of swords in Japan, hosogata-dōken (narrow bronze swords) were imported from Korea sometime near the end of the rst part of the Yayoi period, with Japanese manufacture of bronze swords commencing sometime around the middle of the same period.Excavation of bronze swords with distinct regional markers from various sites makes clear that production was thriving in northern Kyūshū, as well as locations including the Seto Inland Sea and the coast of Ōsaka Bay.While these bronze swords are considered a hallmark of the Yayoi period, it has been established that the middle of this era also saw the spread of iron weapons from China.Consequently, it is di cult to imagine that the de ning property making Futsunomitama-no-tsurugi an advanced weapon was the fact that it was made of iron.ere is a distinct possibility that the army opposing Kamuyamato iwarehiko-no-mikoto would have been armed not just with bronze weapons, but iron swords as well.For example, an iron ring-pommelled sword was excavated from a group of tombs found in Saga Prefecture and dating to the last part of the rst half of the Yayoi period (now an important cultural property of Saga Prefecture).e rst part of the tip of the sword is missing, but its remaining overall length is 50.25 cm.
However, nearly all of these iron swords are Uchizori swords introduced from the early to later Han Dynasty, and are short swords which appear to be intended for one-handed use in cavalry ghts on the Asian continent.Indeed, the traditional academic hypothesis for this kind of ring-pommelled sword was that it was suitable only for one-handed techniques.In contrast, Futsunomitama-no-tsurugi, with its overall length of 84.55 cm, is considerably longer than other known specimens.e hilt portion itself, at 12.73 cm, seems suitable for two-handed use: if one were to take the hilt in the right hand, the pommel would fall naturally into place within the palm of the left hand using the grip prescribed within the Kashima Shinden Bujutsu.At this point, the distance spanned by the hands (16.37 cm) would be appropriate for the sword's blade length, allowing free use of the spiral movements of Kashima Shinden Bujutsu.
e second feature of Futsunomitama-no-tsurugi is the fact that it is an almost straight ring-pommelled sword, with only slight inner curvature.Japanese uchizori swords completed in the Heian period are extremely rare, but stone and bronze swords have been excavated from many ruins dating from the Jōmon period through to the Kofun.A bronze sword, excavated from the "Misakiyama A ruins" in Yamagata Prefecture, serves as a representative example.Sato (1996) describes this small bronze sword (now in the possession of the Tokyo National Museum) as measuring "26 cm in total length, with a blade length of 16.6 cm and maximum blade width of 3.2 cm. e shape has a gentle arc from the hilt to the back of the blade, with the blade entering the hilt portion in a straight line.e blade portion is inwards-curving, with some remnants of the blade remaining visible and sharp."Again, in comparison this emphasises the two key distinctions of Futsunomitama-no-tsurugi: a length suitable for two-handed usage, and an inwards-curving iron blade with a reduced curvature compared to other extant examples.

e Spiritual Transmission of Martial Arts for Usage of Futsunomitama-no-tsurugi
Support for the idea that the style of usage of Futsunomitama-no-tsurugi was linked to Kashima Shinden Bujutsu is found in the seventh volume of the Sendaikujihongi, which references a "Heaven above and Heaven below" puri cation ritual speci cally linked to Takemikazuchi-no-mikoto. is ritual, imparted to Kuni nazu-no-igatsu-omi-no-mikoto (Fig. 6), references the Hasshinden (hall of eight deities) which is a feature of the ōhara'e ritual of the Kashima Grand Shrine (Seki 1976).e Sendaikujihongi notes that in this ritual the "Heaven above" references its religious applications, while the "Heaven below" references its military ones (Fig. 7).With the common connection to Takemikazuchi-no-mikoto, it is reasonable to conclude that Futsunomitama-no-tsurugi and the techniques bequeathed to Kuni nazu-no-igatsu-omi-no-mikoto were related.Just as when performing the Great Puri cation Ritual of the Nation of Japan, the spiral motion of the "Law of Futsunomitama" through the eight divine attitudes of the Hasshinden can be executed with a uni ed motion used for drawing a circle (characterised by wave equations, as used in, for example, the Schrödinger equation).Accordingly, the "attitude of warriors" performing divinely-transmitted martial arts will become "totally devoted" to the "attitudes of the divinities".
Kuni nazu-no-igatsu-omi-no-mikoto was at the time head of the Nakatomi clan, responsible for the maintenance of this ritual, and in the accounts referenced above was later appointed by Emperor Jinmu as the chief o ciant at the Kashima Grand Shrine soon after Emperor Jinmu took the throne, i.e., in 660 BC (Urabe Kanenaga, transcribed 1522).Given this, and the similarities previously noted between the descriptions of the ritual and what is now practiced at the Kashima Grand Shrine, it is not a stretch to assume that this style of swordsmanship would have served as the prototype of Kashima-no-Tachi.Within the Kashima Shinden Bujutsu, techniques can broadly be divided into one of two categories: shinmyō-ken (techniques which aim to defeat the opponent without blocking or striking their sword) or kōmyō-ken.As shinmyō-ken is specically credited to a divine inspiration granted to Kuninazu-no-Mahito (Fig. 8) in the fth century, the dynamics of the usage of Futsunomitama-no-tsurugi must be based exclusively on the principles inherent in kōmyō-ken.From this, the prediction would thus be that the soldiers of the Imperial Army, as led by Kamuyamato iwarehiko-no-mikoto, would have charged towards the enemy in either the shimo (lower) or kami (upper) hassō kamae of the Kashima Shinden Bujutsu, and one step outside the opponent's reach would, as an opening gambit, strike towards the enemy's neck along a parabolic arc with a locus just in front of their midline.Should the enemy be unable to counter this, sen-no-sen victory would be achieved, with the uchizori blade decapitating the enemy as if it were a sickle being used to reap the heads of rice.
A skilled enemy, however, might seek to defeat this attack by cutting into and binding up the initial strike.At this point, the inwards-curving blade of Futsunomitama-no-tsurugi's design becomes relevant.e mechanical principles of cutting in Kashima Shinden Bujutsu mean that at the point of transition from the "backswing", or beginning of the parabolic arc, to the striking forward motion, there is a point where even if one were to release the sword entirely, it would y forward directly towards the opponent.At that point, when holding the sword in two hands, one can rotate the pommel inside the left hand so as to twist the whole sword around, meaning that one would transition from cutting with the sword to striking with the Shinogi (ridgeline) at the very peak of its outwards curvature.e enemy's sword can then be struck and broken using the kurai-tachi technique, with the enemy's attack being de ected away to the rear and left.e outwards curvature of the Shinogi serves to concentrate the force of the impact, and as the impact does not occur on the blade itself, swords modelled on Futsunomitama-no-tsurugi used in this way will not chip.However, a more pronounced curvature would make the rotation of the pommel in the left hand di cult to execute.From here, so long as the movement of the technique is not stopped, the sword will continue through its parabolic motion and cycle around.By then reversing the rotation of the pommel to its original position, the enemy would then be struck down, as in the case of the sen-no-sen victory.
e following is an account of an experiment validating the practicality of this Kashima-no-Tachi (a technique of kōmyō-ken) method of striking with the shinogi (tested using bokutō, by Seki Humitake as shitachi (performing) with Sekiya Ryoichi as uchitachi (attacking), at a special instruction session of the Kashima Shinryū Federation of Martial Sciences, December 20, 2006: [previous section omitted] in the case where uchitachi uses a battle eld cut [suitable against armoured opponents] and shitachi uses [kurai-tachi], it should be mechanically feasible to introduce a strike with the shinogi.Sure enough, the battle eld cut was de ected and disposed of using the shinogi strike.Furthermore, if without advance notice uchitachi used the principle of teppa (iron breaking) in the battle eld cut, then at the moment of the shinogi strike uchitachi's bokutō would violently shake. is shaking bokutō felt as if it were a burning re thong: the right hand would spontaneously release the hilt, and the back portion of the hilt produced a peculiar tactile sensation.A crack appeared at the tsuba expanding towards the C , M V , H S : R S ... rest of the hilt.Following this, when repeating the shinogi striking several times, on each occasion the crack expanded towards the hilt.e fact that the cracking started from the base of the tsuba can be understood as strong destructive power being applied to a discontinuity in the bokutō's structure.And so, despite cutting together at the monouchi (cutting portion) of the swords, this demonstrates that the recorded breaking of even high-quality swords just above the tsuba may be caused by the destructive potential of this phenomenon in some cases.(Ryūtei n.d.)

Conclusion
In summary, by combining archaeological and historical evidence with the curriculum of the Kashima Shinryū, we advance here a thesis in which the "bestowal of Futsunomitama-no-tsurugi" re ects the development of a longer, outwards-curving sword con guration suitable for a style of two-handed usage which became part of the kōmyō-ken curriculum within Kashima Shinden Bujutsu. is represents one of the earliest of the interactions between technology and technique that drives the evolution of bushidō culture.Certainly, it would not have been the last such re nement.
As mentioned previously, after the enthronement of Emperor Jinmu, Kuni nazuno-igatsu-omi-no-mikoto was appointed as the rst head o ciant of the Kashima Grand Shrine.At that time, the eastern part of the Japanese archipelago was controlled by the Emishi (alternatively, Ebisu or Ezo), who violently resisted the eastwards expansion of the Yamato court.Given the role of the Kashima Grand Shrine in the eastern military campaign, it can be expected that the Kuninazu family would then have taught kōmyō-ken to the soldiers ghting against the Emishi, who in turn might have imitated and stolen kōmyō-ken techniques themselves.Substantiating this, there are dozens of family tombs throughout the Kantō and Tōhoku regions which are noted as having extracted from them iron swords with a con guration similar to Futsunomitama-no-tsurugi, examples of which include Maebashi Tenjinyama Kofun in Gunma Prefecture, Ōyasuba Kofun and Aizu Ōtsukayma Kofun in Fukushima Prefecture, and the Mushazuka Kofun complex in Tochigi Prefecture.
As victory over the Emishi ebbed back and forth, it can be expected that there was pressure to re ne and develop kōmyō-ken.is culminated in the divine revelation granted to Kuninazu-no-Mahito, where in Hōjō Tokichika's account he initiated the marvellous techniques called hitotsu-no-tachi, and exerted his ingenuity to receive the revelation of the "Law of Futsunomitama" (Seki 2013).us, the physical re nements of swords in the style "Heaven below" of Futsunomitama-no-tsurugi enabled a new and powerful style of swordsmanship, which was itself then further re ned and expanded (building on yet further innovations in the development of sword technology) to provide a part of the conceptual framework of Kashima Shinden Bujutsu, an enduring part of Japan's bushidō culture.(Hanawa edited, 1793(Hanawa edited, -1819)).
Fig. 6: Amenokoyane-no-mikoto, ancestral deity of Kuninazu-no-igatsu-omi-no-mikoto, is the most loyal deity serving the August Deity "Amaterasu-ōmikami".A part of wood-cut-print scroll Amaterasu-ōmikami published by Maita Shime with the permission of the Ise Grand Shrine in February of 1880.Fig. 7.An example of "Heaven Below" of the Ōharae Ritual of the Kashima Grand Shrine to achieve its military application, with a visual setting for "the Phenomenal World and the Reality World" through the "Hasshinden sphere" upon jūjutsu combat of divine martiality.
Figures and tables

Fig. 4 :
Fig. 4: e whole picture and the pommel and hilt of the mystical sword Futsunomitama-no-tsurugi as excavated from Isonokami shrine.