Along with the Iga, the Koga is one of the most famous names in ninjutsu history. In recent years there has been great interest in the west over ninjutsu, and as a result the interest in Koga has also risen. But the majority of the information commonly available has been wrong. This is particularly true of the internet.

First among the misconceptions is the very name of the area and style. While the rest of Japan looks at the characters used in the name of the region and pronounces it ‘Koga’ (or more correctly ‘Kouga’ with a long ‘o’ sound) the residents have long referred to the area as ‘Kouka’. Most Japanese do not know this, as they deal only with the characters. But it is amazing how many self-proclaimed master of Koga ryu ninjutsu do not know even the proper term for an art they supposedly learned. For the purposes of this article, I will use the term Koga since it is the more commonly used term. 

When Stephen Hayes first introduced Togakure ryu to the west he set up an organization called “The Shadows of Iga” since the Togakure ryu is said to have been passed down through the Iga region of Japan. Many would-be ninja then seem to have set themselves up as Koga ryu, probably to try to explain how their art was so different from that being presented as an Iga style. But in reality, the Iga and Koga regions were very close physically, culturally and politically. Both areas are next to each other and were part of the Suzuka mountain range, with a long shared history. Indeed, until the regions of Japan were determined by the Yamato court along arbitrary lines Iga and Koga were considered part of the same area. Under the new lines drawn, Iga formed a province of itself and Koga was a small part of Omi province just north of Iga. In many ways the Koga area had more in common with Iga than with the rest of Omi. Later Japanese dramas and novels have portrayed the Koga and Iga and being bitter rivals, but aside from a few minor quarrels common to all areas in all of history this was not the case.

Looking at the records of the regions one finds that there are a lot of cases where the ninja of both worked and trained together. Iga and Koga were perhaps the cradle of the birth of what was later to become known as ninjutsu due to a wide variety of circumstances. The people of the region of Iga had long been known as resentful of authority and those that ruled often did so in little more than name.

When Japan started to slide into the morass of the age of wars the locals formed their own government and ruled themselves by a council of the local strong men. One of the rules that this council wrote that has survived is that they would help and support their allies in Koga to the north. The Koga also had a limited form of self rule. Omi was ruled by the Rokaku family at the time, and in return for a pledge of support to his rule they were granted a form of self determination in their internal affairs. This self rule allowed the Koga and Iga to hire themselves out as military specialists to outside powers. Later land records of Koga list certain residents as if they were the vassals of lords outside of their domain. It was in this setting that the Iga and Koga were able to hone their specialized skills. This self rule allowed the Ninja to have an arrangement similar to that of mercenary forces such as the Swiss pike men and German Landsknechts from the middle ages. Self rule for Koga and Iga meant that matters pertaining to the internal rule of the area were secure, but did not mean that all the factions would support each other outside of their land. To a student of military history of the west, finding mercenaries from a region fighting on both sides of a conflict is not surprising. It is much the same with regards to Koga and Iga. One group composed of Iga and Koga might be on one side of a war, with another group fighting against them. Some families had long ties with their employers, and the dual nature of their loyalties with them and to their region caused conflicts as well.

In 1487 the Koga were called to honor their pledge to the Rokaku family and they responded, along with several specialists from Iga. The time was 10 years after the disastrous Onin war. The war, which was nominally over the succession of the Ashikaga shogunate, ignited conflicts that had been long smoldering into open flame. The whole country plunged into the madness of war and that condition continued unabetted until the Tokugawa shoguns were established early in the seventeenth century. Within a few years after the start of the Onin war the Ashikaga Shoguns in Kyoto were almost powerless, but not entirely. The head of the Rokaku family, Takayori, had enraged the shogun Ashikaga Yoshihisa and fled to his province of Omi. There he called up the Ninja of Koga, who also brought along some of their Iga brothers. Yoshihisa followed. He set up camp at Magari village, in Koga.

There the Koga/Iga commando group struck. Using stealth skills they reeked havoc among the defenders. In their raids the ninja burned the defenders provisions, scattered their horses and injured many men. The shogun’s forces were unable to move for a while as a result and kept behind their defensive works around the camp. Possibly as a result of the poor hygienic standards that have plagued military camps from the start of history, Shogun Yoshihisa sickened and eventually died of disease. The reputation of the ninja of the region skyrocketed. Because it happened in an age when curses and magic were thought to have effect even the Shogun’s illness was credited to the skills of the Koga ninja. There may be some exaggeration to this story, and indeed it may be even questioned that it true at all since it is based on stories written later on. But it is a fact that the most effective 53 families of the Koga region who served the Rokaku family were honored and given the title of the ’53 families of Koga.’ Amazingly, according to a later history by the Ashikaga shoguns, there were ninja from Iga serving inside the camp of the Shogun as other ninja from the same region assaulted them! This history has been questioned by later historians for it’s accuracy as well, but it would not be unusual for the time.

This period, the beginning of the age of wars known in Japanese as the Sengoku Jidai, is the real start of good records and accounts of what would later be known as ninjutsu. What form ninjutsu took before this is shrouded in mystery and subject to countless debates. Part of the problem is defining what ninjutsu is. Since man first fought man; stealth, secrecy and sneak attacks have been part of human warfare. All of these form part of Japanese ninjutsu, but trying to determine what distinguishes ninjutsu from other forms of warfare is a matter of great debate.

The Bansenshukai was a book written in the early Edo period after the age of wars and it was shared between the Iga and Koga. In it, it says that a true ninja must be proficient in both Innin and Younin. Innin is the method of entering the enemies area by concealing one’s form, i.e. stealth. Younin is doing the same, while not concealing oneself, i.e. Disguise and espionage. The book takes time to give some examples of well known ninja only to state that if they had truly been great ninja there would be no record of what they did. From a historical viewpoint this presents a problem.

Much of what the ninja of the region did was of a nature to not make it into the records, and that which does appear in them is only one side of the coin. A Koga resident who wandered through a province, making good maps of the roads, counts of the provisions and troops and even a survey of the strong points by stealth and did not get caught doing so left little record. After he turned in his report he would take his pay and all history would note is that perhaps a certain warlord knew exactly where to attack when he invaded a province. By comparison, a ninja raid into a besieged castle that ended up with part of it being burned to the ground is very hard to keep from the records. Thus we are left with little other than the most dramatic episodes with little mention of the espionage aspect to the ninja. Also, early records and such for the region are somewhat scarce and sometimes contradictory.

Since early times the area of Iga and Koga had been fairly close to the capital, but far enough away to not be totally under it’s thumb. It’s area is crossed with mountains and valleys, and before modern times travel was difficult. So since the Nara period (early eighth century) the area had been known as a refuge of those who had fallen out of favor with the court, bandits and soldiers on the losing side of various wars.

The records of the later ninja clans of the area are of little help in trying to determine the evolution of the area. For the most part they are little more than exaggerations. This is true of all the surviving records of the families of the region. Many of the families claimed important ancestors such as Minamoto no Yoshitsune or Kusunoki Masashige. Both of these men were great warriors who were defeated and killed. There may be some truth to such stories.

The ancestors of some of the families might have been vassals to these men who then had to flee and hide after their masters were killed. But as historical documents the family traditions of the Koga and Iga are not given much credit. Part of the problem is that the ninja of Iga and Koga were not really part of a ryuha. The name Koga-ryu was applied later to describe them, but in period accounts they were always known as the Koga group (Koga-shu, Koga gumi) or Iga group. A ryuha is a political and social organization as well as a means of teaching a particular skill.

The training of the ninja, from what scholars have been able to determine, was not that structured. Groups trained together and there probably was a great deal of information exchanged. Most of what went on could be called learning a family tradition and differed from typical ryuha structures. Later histories of arts that had their roots in the area called themselves Koga ryu, but usually added on their family name or a name of their founder with a -ha after it. For example, a family called Tanaka might say that they practiced the Koga ryu, Tanaka-ha. But of course it really was not a ryuha and the names as such came after the end of the age of wars.

During the sengoku jidai the Koga were busy. They fought in areas mainly around the central plain area of Japan. That area was also the center of some of the most vicious fighting seen in Japan as armies vied for control over Kyoto, the emperor and the seat of shogun. During this time, some of the Koga gained employment with the Tokugawa family, which was then using the name ‘Matsudaira.’ In 1562 they helped the future first Tokugawa shogun to secure some hostages that had been held over his head, allowing him to switch alliances from the Imagawa family to that of Oda Nobunaga.

Nobunaga is known to history as the first of the three unifiers of Japan, but he is not known for his patience or gentleness. In time he held sway over most of Japan, including the areas around the capital. He eventually took possession of Omi province, and with it Koga. The Rokaku family had not shown much efforts to expand their domains, but Nobunaga was eager to place all under heaven into his hands. The idea of warriors like the ninja serving other lords and possibly used against him was not a pleasant thought to him. Many of the Koga ninja submitted to Nobunaga.

But at least one, Sugitani Zenjubo, made an attempt on Nobunaga’s life. A person from Koga by the name of Takigawa had urged Nobunaga to go in and completely break the back of the families in the area. Takigawa undoubtably saw himself as being named head after the pacification was complete. But Nobunaga was dissuaded from doing so by Tokugawa Ieyasu.

It was a debt the Koga later were to repay with their loyalty to the Tokugawa house. During the battle of Iga (Tensho Iga no ran) the central prong of Nobunaga’s thrust from the north took them through the Koga region. The Koga fought in support of their brothers to the south, or at least some of them did.

Some prominent names from Koga such as the Mochizuki are mentioned in later accounts. For their trouble, many of the Koga were killed and their villages burned to the ground. The second invasion of Iga massed more soldiers than the province held in population at the time. It was a doomed effort from the start. Many of the ninja, realizing the futile nature of the effort, fled. This is known as the Diaspora of Iga ninja. Ironically, it may have helped the Iga traditions to survive.

Among the Iga who fled some found new employment with outside lords. Some had already been in the employ of outside lords and were welcomed easily and became permanent members of their armies. They ceased to be known really as Iga ninja. Some were still called the Iga groups, but most took on the names of the area they came to, the name of some ancestor or their family name and added on ‘-ryu’ on the end.

This was the start of many traditions such as Kishu-ryu Ninjutsu who had fled to Kii province after Iga was invaded. Nobunaga did not live too long after Iga was destroyed. In 1582 he was killed by one of his vassals. Tokugawa Ieyasu was caught in unfriendly land as the struggle to pick up the pieces after Nobunaga’s death went on. He enlisted the aid of one of his men, Hattori Hanzo of Iga, to piece together a group composed of Iga and Koga ninja to help him escape to his home province in the East.

During the flight, Ieyasu even was able to take the time to recover for a few days at one of the houses of a Koga ninja in his employ. The ninja of Koga had repaid the favor shown them by Ieyasu and they became trusted vassals of the man who later became the head of Japan. Hattori and his Iga ninja were also rewarded, Hattori by becoming a general in charge of the irregular forces from the Iga and Koga region.
About 300 total ninja from Iga and Koga became permanent vassals of the Tokugawa.

In 1600 the Koga served Ieyasu in the defense of Fushimi castle. The castle was on a route vital to the armies of Ishida Mitsunari in the events leading up to Sekigaharathe battle that helped set up the Tokugawa as shogun. Unfortunately it was also deep within the Ishida’s sphere of influence. Ieyasu hoped to draw off as much strength from the armies marching towards Sekigahara in a siege of Fushimi castle, but it was a clear conclusion that the castle would fall and the defenders killed.

Ieyasu offered the man he left in charge, Torii Mototada, more men but was rebuffed with the logic that no matter how many men held the castle it would fall. Despite this, Ieyasu had a great percentage of the warriors from Koga help the defenders. Some serving inside the castle, others harassing the besieger’s camp from outside. As insurance, Ieyasu held their families hostage. About a hundred Koga ninja or more died in this battle that was a forgone conclusion from the start. But they had managed to draw off a lot of the force and give the Tokugawa time to array their forces. In doing so the survivors were again elevated in the graces of the Tokugawa.

In the Winter and Summer sieges of Osaka castle in 1615 men from both Koga and Iga served in the armies of the Tokugawa. In 1638 a ten man group from Koga was sent to help the besiegers of Shimabara castle, where several hundred disaffected peasants and Christians had raised a revolt. The two oldest ninja, in their 60s, were also veterans of Sekigahara. Some have tried to say that the Koga’s inability to understand what the local dialect was made their mission a failure, but this is not true. The Koga did serve admirably. While they were unable to pass themselves off as natives and gather information they did perform some daring raids and were commended for their service.

The army under the Tokugawas at that time was already starting to show the rot that peace tends to bring on, and the castle finally fell after the defenders were reduced to starvation rather than due to any daring assault. After this last battle, the fortunes of the Koga as ninja started to decline. Ironically, their high status helped them in this as they were promoted up into other professions that were more prestigious, but had little to do with ninjutsu.

In Iga, the man in charge of the province welcomed back many of the ninja who had fled during the battle with Nobunaga. He carefully registered them and organized them into what could be called reserve units. They did not receive a stipend like samurai did, but they were expected to serve and hone their skills as intelligence gatherers. Sometimes they received a small supplement to what they grew. But for the most part they had to live their lives as farmers and other members of the non-samurai class. This was an advantage in a way, since it kept them in touch with the common people whom they disguised themselves as.

The Edo period was a time when there was great differences between samurai and non-samurai, and a little mistake in one’s cover could cause it to be blown. The ninja of Iga still lived as peasants and could pass themselves off as them. According to records, they usually worked half a day on whatever they did for a living and then trained with others the rest of the day. The Koga and Iga in the capital soon rose in prestige, and they left their humble origins behind. Some of the Koga were organized into gun corps. Both Iga and Koga served as guards at the shogun’s castle as well as joining the local police forces. A lot of Koga became hatamoto (direct vassals to the shogun). Most samurai of the time served one of the daimyo who in turn owned allegiance to the shogun, but the hatamoto were answerable only to the shogun. This was a great step up from the Iga ninja who were still working on their farms, but it effectively cut them off from being ninja. The hatamoto were underemployed for most of their existence and became a source of problems. Some, but not all, became little better than troublemakers who were protected by their status. When the last shogun tried to organize the hatamoto into a western style infantry unit they blanched at the idea as being beneath them.

In 1716, the real death knoll for the Koga as ninja was rung. Tokugawa Yoshimune became shogun. Unlike previous shoguns he was not of the main line. He came from the Kii branch of the Tokugawas, one of three families specially set up to provide heirs should there be a problem with the main line. Yoshimune brought in a lot of his own people from Kii to run the government in Edo. Among those were the ninja of the Kishu ryu. Yoshimune was one of the most efficient shoguns Japan had ever seen. He set the government back on it’s feet economically and spearheaded efforts to try to revive the martial side of the samurai. By this time the samurai were barely worthy of the name warriors. It was about this time that Yoshimune set up the ‘Oniwaban’ group of ninja based on his Kishu ninja and reorganized the intelligence service to more
accurately serve the nation, not as an espionage unit, but as an internal security unit. This shift in organization was an important one, and it did not start under Yoshimune, only strengthened. In the Edo period the Metsuke system was the primary way that the Tokugawa kept control and maintained the peace.

The metsuke was not a secret agent. His role was kind of a cross between a FBI agent and an ambassador. His role was very high profile in the court of the daimyo he was sent to serve. While he could not hide in the shadows like the ninja of old, it was very hard for the daimyo to plot anything while he was constantly around and keeping his eyes open. His role as a representative of the central powers may have made him less easy to fit into a disguise, but it did insure a degree of safety from harm. Metsuke were rarely antagonistic to the lords they were sent to look over. They were very keen on maintaining good relations with everyone. An example of the metsuke from the movies is the evil leader of the plot in the movie “Sanjuro” starring Toshiro Mifune.

Ninjas in the past entered into enemy territory to map and survey things. The Bansenshukai lists things like how to estimate the height of buildings and width of things like rivers and moats by means of a form of geometry. Distance on a road could be kept by knowing how to count steps and convert them into standard
measurements. A ninja could walk through a province and come out with a fairly accurate map of the area and survey the castles by entering using stealth. However, the metsuke of the Edo period stood over the surveyors and took notes while they worked and openly sent maps and such that they had gathered to the shogunate. All work on fortifications had to be approved and monitored by the representatives of the shogun, and they took very accurate notes while any such surveying and building was going on. On occasion, the metsuke took on the role of a investigative agent. But that was all very overt in it’s nature. Sometimes the shogunate wished to destroy particularly troublesome clans and needed an excuse gathered by the metsuke to do so. But more often the shogunate feared the result of large numbers of samurai suddenly forced into ronin status and so they worked with the clans elders to seek out and correct problems before they occurred. In some cases, what was good for the clan was not the best thing for the lord in power and sometimes clans would force their own corrupt daimyos to retire and make way for their heirs.

According to records, sometimes the ninja still in Iga would be requisitioned to assist in determining the mood of the peasants. The Tokugawa were scared to death of the idea of a peasant revolt. Several occurred during the Edo period. The ninja of Iga did not enter castles like they used to, but they did serve as a way of finding out what the peasants were thinking. If an agent disguised as a traveling peddler reported that at
every stop of his journey he had heard bad stories about the local daimyo then the shogunate knew they had a potential riot on their hands.

Some traditions from Koga were not part of the Tokugawa but instead took service with other lords where they kept their skills alive outside of the influence of Edo. These schools then ceased to be known as Koga ryu and instead followed the example of many of the Iga ninja during the Diaspora who took separate names based on the lord they served or the name of an ancestor. As such, they really ceased to be classified as members of the Koga ryu. So it went on for decades, centuries even. The need for entering enemy territory and completing missions of espionage and sabotage was effectively taken away from the Koga. Their status was considerable in the Shogunate, but people like Hichiro Okuse are clear when they state that the Koga were not ninja by the end of the era. Lessons that had been learned in blood had been
lost and they had become little more than security guards and bureaucrats.

When Commodore Perry sailed into Edo harbor in order to open up Japan for trade, it was a ninja from Iga by the name of Sawamura Jinsaburo Yasusuke who was called on to gather information on them. Records collected in the first year of the new era of Meiji lists large numbers of these Iga ninja grouped by their village. No similar records of the Koga region exist.

With Perry came great change. Many systems of combat now had no purpose in the modern era and were lost. Others became sports. Some became a means of tradition and some were kept alive by their keepers as a link with Japan’s martial past. The ninja that could be called ninja belonged to a former age and had no place in the new world. The ninja had mainly spied on other Japanese. In the modern world the Japanese had to worry about languages and cultures that the ancient ninja had never even thought of.

Read more for Part II…

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