As a nation with a long and rich history of sword-making, Japan has developed a deeply rooted tradition of craftsmanship and artistry. The history of the Japanese sword is divided into distinct periods based on Japan's historical development:
Ancient Sword Period (A general term for swords before the late Heian period)
Old Sword Period (From the late Heian period to 1595, the 4th year of the Bunroku era, spanning the Heian period, Kamakura shogunate, Nanboku-cho period, Muromachi period, Sengoku period, and part of the Azuchi-Momoyama period)
New Sword Period (From 1596, the 1st year of the Keichō era, to 1780, the 9th year of the An'ei era, spanning part of the Azuchi-Momoyama period and part of the Edo shogunate period)
New-New Sword Period (From 1781, the 1st year of the Tenmei era, to 1876, the 9th year of the Meiji era, when the Sword Abolishment Edict was issued)
Modern Sword Period (After the 1876 "Sword Prohibition Edict," excluding the standardized military "Showa swords")
This period is not classified within the traditional history of Japanese swords, as the types of swords and blades during this time were highly diverse, with complex shapes and structures. On one hand, there were swords with forms nearly identical to those from the Han to Tang dynasties in China. Excavations have uncovered ring-pommel swords as well as the so-called "Tang Da Dao" (imported Tang swords) and "Tang-style Da Dao" (domestically produced imitations of Tang swords). On the other hand, in the northern Kanto region and Hokkaido, Warabiteto was also present. These swords are generally believed to have been either crafted by the Ainu people or adapted from Ainu weapons.
Overall, swords from this period exhibited little to no curvature (sori), meaning they were generally straight-bladed. Most did not adopt a composite construction (i.e., they lacked a soft-core steel structure). Many swords had tangs that directly served as handles, and a significant number were primarily designed for thrusting attacks. The usage of swords during this era was predominantly for infantry combat, and the carrying method was similar to the "tachi-style", where the sword was suspended from the waist.
However, the Ancient Sword Period, particularly during the Heian period, is regarded as the gestational stage for uniquely Japanese-style swords. There were two main driving factors. The first one is the rise of cavalry warfare – Stimulated by the influence of Ainu cavalry forces, the Japanese central imperial military increasingly relied on cavalry as its main force. This created a demand for weapons suited for mounted combat, particularly for cutting and slashing down at infantry.
The other one is the saturation of Chinese blade-making techniques – By this time, Japan had absorbed and mastered Chinese sword-making techniques, prompting native swordsmiths to begin crafting blades tailored to local needs.
The Warabiteto, with its characteristic angled transition between hilt and blade, is considered a significant precursor to the later "classic" Japanese sword shape. By the end of the Ancient Sword Period, the "Keibatsuke Tachi" had emerged. This sword evolved directly from the Warabite-to and already closely resembled the iconic Japanese sword forms of later generations.
The oldest surviving Japanese sword, Kogarasumaru , is believed to have been forged between the late Nara period and the mid Heian period. According to legend, the sword's name derives from its mystical origin—it is said to have appeared within the feathers of a great eight-foot-long crow sent by Ise Grand Shrine.
Kogarasumaru is often considered the "missing link" in the evolution of the Japanese sword. Its kissaki (tip) is double-edged, resembling both the straight swords introduced from China and the Tang Da Dao (Tang broad swords), making it highly effective for thrusting. However, its curved blade reflects the signature form of later Japanese swords, allowing for slashing and cutting techniques. In this way, it is akin to an Archaeopteryx, embodying traits of two different evolutionary stages.
The swordsmith who forged Kogarasumaru, Amakuni, is regarded as the forefather of Japanese swordsmithing. In the later classification of Japanese sword-making traditions, known as the "Five Schools" (Gokaden, based on their characteristics and historical origins, the schools of the Koto period are classified into one of five traditions: Yamato, Yamashiro, Bizen, Soshu, and Mino.), Amakuni is associated with the Yamato Tradition of Nara. This tradition is believed to be the oldest sword-making style in Japan’s history.
The Kotō Period is the most significant phase in the history of Japanese sword development. Spanning from the late Heian period to 1595 (Bunroku 4), it encompasses the Heian period, Kamakura shogunate, Nanboku-chō period, Muromachi period, Sengoku period, and part of the Azuchi-Momoyama period—an era marked by continuous warfare. This turbulent backdrop provided an extensive practical testing ground for the refinement and evolution of Japanese swords.
This period also saw the emergence of the Five Sword Schools, the foundational classification system for different styles of Japanese sword-making. The oldest of these, the Yamato tradition , was followed by the Bizen, Yamashiro, Sōshū, and the last to appear, Mino traditions. It was during this era that the most iconic features of the Japanese sword—a prominent hamon (tempering pattern) and an elegant curvature (sori)—were fully developed and became standardized.
1. Late Heian to Early Kamakura Period
During the late Heian period and early Kamakura period, the prolonged conflicts between the Minamoto (Genji) and Taira (Heike) clans led to an increasing demand for superior weapons. The tachi, the predecessor of the modern katana, officially emerged during this time. The dominant sword-making traditions of the era were Yamato, Yamashiro, and Bizen.
Swords from this period were characterized by elegant proportions, featuring a narrow kissaki (tip), a long and slender blade, high-quality steel, and refined hamon patterns. The blade’s width was noticeably wider at the base (motohaba) than at the tip (sakihaba), and it exhibited a strong curve at the waist (koshi-zori). This distinctive shape, resembling a person standing tall with legs apart, was known as “Tachihari”.
2. Early Kamakura Period
By the early Kamakura period, after the Genji faction gained actual control over Japan's government, the samurai class (bushi, or warrior class) it represented began to struggle with the court nobility (kōke), which represented the power of the emperor. Internal conflicts within the Kamakura Shogunate continued, and the demand for high-quality swords remained immense. During this period, the 82nd Emperor of Japan, Emperor Gotoba (reigned from 1183 to 1198), a lover of Japanese swords and a swordsmith, summoned renowned swordsmiths from all over the country in the second year of Jōgen (1208 AD) to forge swords in the region of Yamashiro Province (now Mino City, Osaka Prefecture) and established the famous “ban-tanegashi” system.
The "ban-tanegashi" system involved one famous swordsmith taking the lead each month as the “ban-tanegashi” to forge swords, while two other ministers served as the “tōkaji hōjō” (official swordmasters) for two-month terms. This system continued formally for about 15 years, ending after the Jōkyū War (1221 AD), when Emperor Gotoba was exiled after failing to defeat the shogunate. It is also worth mentioning that Emperor Gotoba himself crafted swords, which came to be known as “Kiku-no-Misaka,” and as the emperor personally forged swords, the social status of swordsmiths was elevated, further promoting advancements in Japanese sword-making techniques. Emperor Gotoba is thus regarded as a highly revered figure in the history of Japanese swords.
The overall shape of Japanese swords during this period did not differ greatly from previous designs, with the tachi still being forged. However, due to the increased feedback from actual combat, swordsmiths began to adjust the thickness and curvature of the blades, striving to achieve a balance of sharpness and strength. The tempering patterns (hamon) also started to show distinctive characteristics. The sword-making styles of the provinces of Yamato, Yamashiro, and Bizen gradually became more refined and personalized, with the forging techniques improving continuously. During this time, the tip of the sword became slightly larger, the blade width increased marginally, and adjustments in the tip’s position shifted the center of gravity forward. The blade length was generally around 80 cm, and there were also cases of official regulations defining set dimensions. Additionally, the earliest Japanese short swords (tantō) and naginata (polearms) emerged during this period.
3. Mid Kamakura Period
During this period, the Hōjō regime, relying on the power of the samurai class, formally took control of Japan, leading to a brief period of peace. At the same time, due to the growing power of the warrior class, the demand for fine swords did not diminish. This led to Japanese swords of this period often featuring grand shapes, exquisite hamon, and beautiful ji-hada. The blades became wider, and the tip (koshizori) changed from small and delicate to short and wide, resembling a "boar’s head" (inoshishi-kubi), with the overall shape of the sword shifting from classical elegance to bold and magnificent, in line with the aesthetic style of the warrior class. Famous swordsmiths such as Kurita-guchi Kunisada, Bizen-zenjō Kunimune, and Fukuoka Ittō-monji, among others, were also ordered by the shogunate to move to Kamakura, where they enhanced their forging techniques through ongoing exchanges and eventually became the origin of the new swordsmith tradition known as the Sōshū school.
During this era, samurai often decided the outcome of battles through single combat, known as "ikkidō" (single rider combat). Therefore, the bold and magnificent swords of this period were designed to counter the ever-evolving armor. The blades became thicker, with the difference between the base width (motohaba) and tip width (sakihaba) becoming smaller. The "boar’s head" tip, which was less likely to break during armor-piercing strikes, and larger blade angles became popular. During this time, tanto (short swords) and naginata (polearms) experienced new developments, and with the increase in length and thickness of the tachi, the demand for self-defense weapons began to rise. The prototype of the later wakizashi (side-sword) also appeared during this period.
4. Late Kamakura Period
For Japan at this time, the most significant events were the fall of the Southern Song dynasty and the two Mongol invasions. Despite the bravery of the samurai, whose combat methods were outdated, and their small-scale victories, they were powerless against the Mongol army's combined forces during the first invasion. Fortunately, the Mongol army was unprepared, and internal conflicts arose. Additionally, a typhoon struck as the Mongols retreated, leading to the failure of their initial invasion of Japan.
After the fall of the Southern Song dynasty, during the second invasion of Japan, Japan had learned from previous experiences and made thorough preparations (such as the "Mongol Defense Rampart" coastal fortifications, improved bows, and more flexible and varied guerrilla tactics). Moreover, the Mongol army had a change in leadership, the Korean ships were poorly constructed, and another typhoon arrived. With the favorable conditions of time, place, and people, Japan's samurai finally achieved victory in the Battle of Kōan, reaching the pinnacle of their historical glory.
It was also because of these two Mongol invasions that the technology for making Japanese swords underwent another transformation due to the realities of combat. The "Inokubi" kissaki (boar’s head tip) of the tachi was prone to breaking at the tip, leading to the complete destruction of the sword, and as a result, this design gradually disappeared. As for the hamon, certain intricate, beautiful patterns were achieved by sacrificing the overall hardness of the blade during the soil-hardening process (quenching), which made these swords prone to breaking unexpectedly in intense combat, thereby threatening the life of the wielder. In response to these issues, swordsmiths of the time abandoned some of the ornamental appearances and began to focus on enhancing the sword's sharpness, hardness, and strength. The famous swords known for their cutting ability during the old sword period (Koto) were mainly forged by a few swordsmiths from this period.
The Sōshū tradition also officially emerged during this period. It used steel with varying hardness, which was densely folded and forged, and then subjected to high temperatures to forge the blade. This process resulted in a product that not only had a characteristic pattern structure of the tradition but also achieved the conflicting qualities of high hardness and high strength. After being tested in battle, these swords became highly sought after by the samurai. The craftsmanship style of the Sōshū tradition was learned and adopted by other schools, thus improving the overall practical performance of Japanese swords. Of course, weapons such as short swords, naginata, small tachi, nagamaki, and others continued to evolve in the practical battlefield context, driven by external threats.
5. The Nanboku-cho Period (Northern and Southern Courts Period)
After the fall of the Kamakura Shogunate, Japan entered the Nanboku-chō period due to intensified conflicts between the warrior government (buke) and the court nobility (koke), as well as issues regarding the imperial succession. The country was once again engulfed in war. A defining feature of this period was the large-sized, bold tachi and ō-tachi (great swords), whose clear tactical purpose was to allow mounted warriors to engage in large-scale attacks on enemy infantry formations. The increasing size of the ō-tachi reflected the rapid development of pole weapons like the naginata. To counter the foot soldiers wielding long weapons, mounted samurai had to either lengthen their tachi or make them larger overall. It was common to see tachi with blade lengths of up to 1.5 meters, and some samurai even used naginata as their primary weapon.
The swords of this period can be summarized with three words: long, wide, and large. The tachi blades became longer, wider, and typically featured larger tips, with thinner thickness. There was an emphasis on cutting ability, and the swords’ overall appearance became more bold and powerful.
The successor to the tachi, the katana (and the classic form of the wakizashi), also began to appear due to the increasing need for infantry combat. The katana became a secondary weapon for foot soldiers, as its shorter length allowed for easier handling in close combat. If infantry and cavalry became entangled in a melee and lost their long weapons, they could still use their katana for thrusting, providing a final opportunity for survival. In the realm of short swords, practical variants such as the tsunagi (extended short sword) and the tōsō (armor-piercing short sword) were developed to allow warriors to have a better chance of survival and to kill on the ever-changing battlefield.
The myth of the Sōshū tradition continued to thrive during this period, reaching its peak. Meanwhile, swordsmiths of the Bizen tradition further studied and imitated the Sōshū style, leading to what later generations called "Sōshū-Bizen." In contrast, while the Yamashiro and Yamato traditions also absorbed techniques from the Sōshū tradition and produced notable works, they were generally in decline during this period.
6. The Muromachi Period
With the rise of the Ashikaga Shogunate, Japan once again entered a period of relative peace. The large-scale infantry tactics completely buried the previous samurai techniques of individual mounted archery. Whether for small-scale combat or law enforcement activities during peacetime, or for large-scale field battles dominated by infantry, these changes pushed for the further development and expansion of the traditional Japanese swordsmanship system, which in turn placed new demands on weaponry. During this period, while the katana still resembled the tachi in form, the appearance of dedicated sword fittings and carrying methods for the katana signaled its growing prominence in the future.
At the same time, the wakizashi began to further differentiate itself due to practical use, especially in terms of length, making a clear distinction from the longer swords. Short swords and naginata also saw developments in their appearance, while the longbow started to be replaced by the long spear.
In terms of shape, early Muromachi-period swords had relatively slender blade with a small tip (inspired by the early Kamakura period), characterized by elegance. The curvature of the blade was primarily in the middle (distinct from the early Kamakura period). During the mid-Muromachi period, the blades became wider, the tips larger, and the curvature began to diminish. By the late Muromachi period, the blades had become even wider, and the tips grew larger as well. Additionally, in the mid and late periods, the "karate-uchi" (single-handed draw and strike) technique emerged, and the blades were later categorized by length into katana or wakizashi.
During this era, the myth of the Sōshū tradition faded, and what was known as "End Sōshū" emerged. The Bizen tradition saw a resurgence, particularly the Osafune school, which became the representative faction of the Bizen tradition during this time. Additionally, the youngest of the "Five Traditions" (Gokaden)—the Mino tradition—officially entered the historical stage. Descendants of Shizu Saburō Kaneuji from the Jōtō school moved to the Mino region, combining the techniques of the Yamato and Sōshū schools, thus creating their own distinct style.
Moreover, during the Muromachi period, the Osafune and Mino schools produced a large quantity of practical-use swords known as "kazu-uchi-mono" (mass-produced swords). These swords, often bundled together by merchants and sold in bulk, found their way in large numbers to the Ming Dynasty.
7. Sengoku Period and Part of the Azuchi-Momoyama Period
At the end of the Muromachi period, Japan entered the famous Sengoku era, where various warlords vied for power, each hoping to unify the country. The katana began to gradually evolve away from the appearance of the tachi in the mid-Muromachi period and became the dominant sword on the battlefield. However, its length was longer compared to later periods, with a stronger focus on practical combat. Various types of short swords, wakizashi, katate-uchi (single-handed swords) emerged, all of which were designed with a strong practical combat focus. The spear, or yari, became popular among both samurai and foot soldiers, becoming the main weapon for most soldiers in battle. The large, long spears became a distinctive feature of this era.
During this period, there was little change in the forging techniques of various sword traditions, though there was a stronger emphasis on practical combat use, particularly cutting ability. A famous example is the Muramasa swords, renowned for their sharpness, so much so that samurai using them in training would suffer significantly more injuries than those using swords from other regions. The Mino tradition, known for creating many unadorned but highly functional battle swords, also experienced its most glorious period during this time.
Overall, however, swords became a secondary weapon on the battlefield. Japanese armies during the Sengoku period were heavily equipped with firearms introduced from the West. At their peak in some battles, around 40% of the ashigaru (foot soldiers) were armed with firearms. The long spear, praised for its ease of use, lower cost, and ability to counter cavalry, became the primary choice for most ashigaru.
During the Azuchi-Momoyama period, when Toyotomi Hideyoshi unified Japan, many "family heirloom" long tachi from the Nanboku-chō period were retrieved, sharpened, shortened, and modified for use with excellent results. As a result, many swordsmiths began to imitate the post-modified shape of these long tachi when forging new swords. The swords from this period are known as the Keichō Shintō (Keichō New Sword). Furthermore, the katana and wakizashi underwent further development, with the wakizashi's shape gradually resembling the shortened long swords from the Nanboku-chō period. A dual carrying system of the katana and wakizashi, known as "dai-saku-bon-dachi" (large and small swords), also emerged.
In 1588 (Tensho 16), Toyotomi Hideyoshi issued the famous "Sword Hunt Edict" (Katana-gari rei), which prohibited non-samurai classes (such as merchants and farmers) from owning Japanese swords, firearms, and spears.
During this period, swordsmiths frequently migrated, spreading their forging techniques, and local iron ores were traded more easily due to improved transportation networks. The distinct characteristics of the Five Traditions (Gokaden) from the old sword period began to blur, while the forging characteristics of the Shintō (New Sword) period began to emerge. However, some swordsmiths continued to follow the old methods of forging. Additionally, iron blocks imported from Portugal, the Netherlands, and other regions were called "Nanban-tetsu" (Southern Barbarian Iron) and used by a few swordsmiths, with some even combining "Nanban-tetsu" with traditional Japanese "tama-hagane" to forge swords.
From 1596 (Keicho 1) to 1780 (An'ei 9), Japanese swords entered the next period—the Shinto period, which primarily corresponds to the Edo period, with some time also from the late Azuchi-Momoyama period. During this period, the development of classical Japanese swordsmanship reached a certain height. The swords forged to meet this demand were generally similar to the classic katana, measuring around 60 cm in length, with a small curve and fittings typical of katana, perfectly suited for the tactical needs of sword-drawing, quick thrusting, and cutting. The swords were primarily used in environments outside of large-scale warfare, including law enforcement activities, security, and small-scale skirmishes.
At the same time, the Tokugawa shogunate strictly regulated the shape of long swords, wakizashi, and short swords, and once again decreed that non-samurai classes were prohibited from carrying long swords. However, as the merchant class grew in power, these wealthy non-samurai often chose ornate wakizashi, especially those close to the length of katana, for cultural refinement or personal defense.
In 1657 (Meireki 3), a large fire broke out in Edo Castle, causing significant casualties and destroying many samurai swords. This disaster led to a sharp increase in market demand for swords, and the "Kanbun Shintō" category of swords emerged. These swords had thick blades, small curves, and emphasized practicality, with overall high quality. Many of these swords achieved excellent cutting results in "corpse tests" (test cutting on cadavers), leading to the appearance of many cutting inscriptions. The Shintō swords of this time still inherited the emphasis on practicality from the Keichō Shintō period and saw the rise of famous swordsmiths like "Tora Tetsu" and other renowned swordmakers. Additionally, it was common for different classical swordsmanship schools to practice with bamboo or wooden swords in mock combat, indirectly promoting the consideration of practicality when forging swords.
However, with the peace established over many years and the Tokugawa shogunate's strict prohibition of duels, the focus of swords gradually shifted from practicality to aesthetics and artistry. The hamon (blade pattern) was no longer concerned with the rational distribution of hardness but instead focused on artistic patterns and beauty. The shape of the sword also shifted toward retro styles for the sake of elegance, with many blades featuring engravings, further reducing their practical use. These swords came to be known as "Genroku Shinto," and in some ways, this marked a period of decline for Japanese swords.
In the late Edo period, the political and cultural theory of "restoring the monarchy and revering the king" spread widely, and a wave of nostalgia for ancient traditions emerged in the swordsmithing field. A key figure in this movement was Suishinshi Masahide, who visited swordsmiths still using traditional methods passed down through generations. He strongly advocated for the "revival of ancient forging techniques" and incorporated ancient tools such as iron nails and iron pots, preserved by old swordsmiths, into the forging process. This addition, known as "Shitei," helped give the new swords a color closer to those from the ancient sword periods.
As other swordsmiths followed suit, the "revival forging technique" spread widely, and new swords began to take on the grandeur of ancient blades, with simpler, more rustic temper lines. Later, during the Bakumatsu period, the genius swordsmith Minamoto Kiyomaro used his research to create exceptionally high-quality works. His swords not only reproduced the grand style of ancient blades, both in appearance and temper line but also displayed remarkable temperature control. Furthermore, during practical tests, Kiyomaro's swords proved to be highly effective in combat. He is considered one of the leading figures of the New Sword Era and one of the greatest swordsmiths in history.
However, despite the bloody political struggles of the late Edo period, which showcased the practical value of traditional swordsmanship and the Japanese katana, and the resurgence of martial arts, the times had changed. Even the skilled swordsmen of the Shinsengumi could not compete with the newly formed modern military forces, which triumphed in the Boshin War. Swords were no longer the focal point of warfare. For Japan moved towards modernization, the samurai and their katana slowly became seen as obstacles to progress.
After the "Sword Abolishment Order" in 1876, the "Satsuma Rebellion" (1877) broke out. In this war, former samurai using Kenjutsu (the way of the sword) fought to the death against police officers from the former Shogunate (the 3rd Division of the Bessō Battalion) who were armed with Japanese swords. This tragic battle, under the rule of feudal lords, was both the last large-scale use of the Japanese katana in modern warfare and a symbol of the decline of the samurai class and traditional Japanese swords. As for the death and rebirth of traditional Japanese swordsmanship, that is another topic entirely.
After the strict enforcement of the "Sword Abolishment Order," only a few swordsmiths continued to forge swords using traditional techniques. During World War II, the majority of the military swords used by the Japanese army were non-traditional, mass-produced "Showa swords," with only a small portion made by reusing ancient sword blades fitted with military-style fittings or crafted using traditional forging methods. Following Japan's defeat in the war, the subsequent democratization and reforms, as well as the improvement of laws regulating firearms and weapons, led to the transition of modern swords made through traditional techniques. These swords shed their association with warfare and became "art swords," serving as a means of preserving Japan's traditional culture.
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