Carl von Clausewitz - On the nature of war

Prussia has produced notable personalities that influenced history, such as chancellor Bismarck and general Clausewitz. This is the first post in a series that focuses on Carl von Clausewitz's military theory treatise, On War. Here I summarize the contents of the first book, that discusses the nature of war.

Chapter 1: What is war?

• the definition of war
• acknowledges the need for the maximum use of force
• it is through their interaction that warring sides push each other to extremes
• the aim is to overcome or disarm the enemy (making him defenseless)
• was is not an isolated act and it doesn't consist of a single decisive blow
• the result of war is not final
• the similarity between war and a gamble
• war as a means of reaching a political goal

Chapter 2: Purpose and means in war

• the 3 objectives that must be considered: the armed forces, the country, and the enemy's will
• war doesn't involve the notion that the 2 states have relatively equal strength
• methods to increase the cost of the war for the enemy
• combat is the only means of war

Chapter 3: On military genius

• military genius consists of a combination of elements that influence military performance
• war being the realm of chance
• the importance of the intellect in war
• the role of the commander
• temperament and feelings's influence in war
• relationship between warfare and terrain

Chapter 4: On danger in war

• the effect that immediate danger has on the mind of a soldier

Chapter 5: On physical effort in war

• physical effort can't be measured
• hardships are no excuse for a defeat, bu they boost the value of a victory

Chapter 6: Intelligence in war

• the unreliable character of information in war
• most intelligence is false, and reports of bad news multiply easily

Chapter 7: Friction in war

• even the simplest thing is difficult in war
• how performance in war is lowered by many factors 
• habit and experience are essential for sound decision-making

Chapter 8: Concluding observations on Book One

• danger, physical exertion, intelligence, and friction are the elements that impede activity in war. They can be countered by combat experience

Source(s):
On War

Book recommendation - Soldiers & Ghosts: A History of Battle in Classical Antiquity

This book presents the evolution of warfare methods in Greece and Rome. It depicts battles, campaigns and military practices in detail, while also bringing up interesting topics, such as how the emulation of the glorious past influenced the behavior of troops and leaders in both the Greek and Roman civilizations. I summarized the chapters below:

Chapter 1: Fighting in the Iliad

• Homer's epic poem depicts fights between heroes as one-on-one duels
• competition in excellence between the combatants
• slaying a strong opponent brings more glory to the victor
• the Iliad set the foundation for the spirit of competition among the Greeks

Chapter 2: The Last Hoplite - The Origins of the Phalanx

• the story of the 300 vs. 300 battle between Spartans and Argives, at the end of which Othryades, a lone Spartan survivor, remained standing in his place among the hoplite ranks
• emergence of phalanx combat
• cavalry and archer corps gradually give way to the heavy-armored infantry suited to disciplined fighting in a formation
• holding one's place in the ranks is the supreme display of courage in phalanx combat and a way to compete between each other

Chapter 3: Two Stubborn Spartans in the Persian War - City and Discipline in the Phalanx

• the hoplites' acts of courage or cowardice reflect on the reputation of their cities
• Spartans marched and fought in a calm and disciplined way, without being driven by anger or passion
• Spartan obedience to the laws and commanders was a competition of excellence

Chapter 4: The Guile of Delium - Generals and Tactics in the Phalanx

• focus on the first part of the  Peloponnesian war
• in the battle between Athenians and Boeotians, the Thebans used an unprecedented tactic of a 25 deep phalanx. The Athenians were routed, but Socrates rallied them and led them to safety
• normal conventions of warfare are discarded in favor of more cunning methods with a better chance for victory
• examples of Spartan tricks and deception in battle
• the kings and commanders also fought in the phalanx, being part of the hoplite competition of valor
• cunning on the general's part interfered with the hoplite code of bravery that was implied by standing one's ground in battle
• competition between leaders manifested in skills such as troop deployment, persuasion and stratagems

Chapter 5: The Arts of War in the Early Fourth Century BC - Peltasts, Cavalry, and Training

• focus on the last part of the  Peloponnesian war
• changes in warfare are introduced. Sparta reestablishes troops of archers and cavalry
• emergence of light troops and mercenaries
• in the battle of Lechaeum, the Athenian peltasts inflicted heavy damage on the Spartan hoplites, who were unaccustomed to opponents who used hit-and-run tactics
• description of cavalry tactics, formations, and drills
• instilling discipline to unruly troops by making drills a competition, sometimes with an audience
• competition between cities by the way of hoplite fighting gradually gives way to individual competition between soldiers in their area of expertise
• the military maneuvers that led to Sparta's defeat by Thebes at Leuctra 
• description of the Theban Sacred Band made up of 300 male lovers

Chapter 6: Alexander the Great at the Battle of Issus - Homer and Macedonian Warfare

• Alexander's campaigns and tactics 
• Alexander's fixation with Achylles and the competition with his achievements
• story of how Alexander fought in one of his battles wearing an ancient armor that was thought to have been used in the battle of Troy
• description of how Alexander's army was organized
• the practice of ranking and rewarding merit, in order from the first to the eight, and punishment that implied losing one's position in the army and of the status that came with it

Chapter 7: Hellenistic Warfare (323-31 BC) - Competition, Combat and Innovation

• covers the battles over Alexander's empire
• emergence of various military disciplines in which games and contests were held, such as the games of Samos
• the loose discipline of the Hellenistic troops was compensated by their competition in obedience to commands and precision of execution
• the competition in stratagems and army deployment between generals Antigonus and Eumenes
• the importance of training for armies likened to that for professional athletes

Chapter 8: Early Roman Warfare - Single Combat and the Legion of Maniples

• tales of single combat duels between Romans and their foes
• spoils taken from winning duels granted special honors for a Roman warrior
• the organization of a legion of maniples and its combat methods
• the Romans' conception of their past
• 2 dominant aspects of Roman warfare: virtus and disciplina

Chapter 9: The Wrath of Pydna - Command, Discipline and Courage in the Roman Republic

• focus on the war between Rome and Macedonia
• the connection between war and public opinion in Roman society
• the Romans' aggressive behavior in war and disdain for caution
• the superiority of the Macedonian phalanx against the Romans until the defeat at Pydna
• conflict between the notion of virtus and the need for tactics in warfare

Chapter 10: Caesar's Centurions and the Legion of Cohorts - Military Culture and Greek Influence in the Late Republic

• describes Caesar's campaigns
• the aggressive bravery and high casualty rate of Roman centurions
• the organization of a legion and the cohorts' versatility

Chapter 11: Scenes from the Jewish War, AD 67-70: Fighting, Working and Training in the Roman Imperial Army

• chronicles the Jewish War
• increasingly important role of auxiliaries, supported by the scenes on Trajan's Column
• competition in disciplina for the legions and in virtus for the auxiliaries

Chapter 12: Shield Wall and Mask - The Military Past in the Roman Empire

• Roman combat style switching to the shield wall
• testudo - the tortoise formation
• masks that signified the excellence in horsemanship of the wearer, and the influence of the Greek history and mythology
• tendency to revive Greek traditions of fighting

Chapter 13: Julian in Persia, AD 363 - Triumph of the Ghosts

• description of emperor Julian's campaign in Persia
• Julian's emulation of the past in warfare
• the battle of Adrianople

I found this book an excellent read about the methods and transitions of warfare from the heroic times of the Iliad, through to Alexander the Great's conquests, and Rome's evolution from republic to empire. It also includes quotes and interesting, less known facts (or they were for me). Did you know that Alexander carried the Iliad with him on campaign to have a constant source of motivation and inspiration? Or how the last surviving Spartan hoplite of a 300 vs. 300 battle between Spartans and Argives claimed the right to victory, even though from the Argives there remained 2 survivors? I really enjoyed this book and all the information that it provided, in an easily readable way, and I highly recommend it for others who are interested in the subject.

Check it out here:

Two swords in modern kendo

             Fighting with two shinai is seldom seen in kendo nowadays. There has been a period when it was popular, but it remains a minority now, difficult both to wield and to judge properly. First of all, in the Nippon Kendō Kata, there are seven techniques with the tachi, and three with the kodachi, but none for the simultaneous use of the two swords. As two-sword fighting remained a rare phenomenon in kenjutsu, it didn't bloom to spectacular popularity in kendo either. The kata were chosen from the most representative techniques that would illustrate good posture, proper interval and cutting technique, and there was no place for scarcely used two-sword techniques.

            At the beginning of the Shōwa period however,  nitō kendo was popular in the students competitions. At that time, there was a sole focus on victory, by any means, among the students, and the reason many of them took nitō was to secure the win of the match against the opponent, by confusing him and putting him in a difficult spot, because not many competitors knew how to fight against someone wielding two shinai. As a result, the schools and universities began to train their students in nitō, to be able to confront a dual wielding opponent. The fixation on victory by using tactics that were unexpected by the opponent was so strong, that in 1930, nitō was banned in student matches. Since the students were only using two shinai as a means for obtaining victory, and were preoccupied by winning the match only, they were neglecting the mental and spiritual development that accompanies the practice of kendo. The ban was lifted in 1991, per the efforts of the All-Japan Student Kendo Federation, which feared that nitō kendo would become extinct, with so few opportunities to learn and practice it.

            From the rules perspective, nitō kendo experienced a slow and lengthy development. One-handed techniques were not approved in official matches until 1919, but they remained frowned upon and to be generally avoided. The criteria for the length and weight of the two shinai were only established in 1943, and they have been revised to accommodate the women practice of nitō as well. With being subjected to regulations similar to sports disciplines, nitō kendo could now become a viable choice in official competitions as well. However, it remains a minority in today's kendo. The validity of the strikes is difficult to judge, and the strikes with the short shinai are generally not considered valid. Although there is a stipulation about the short shinai in the rules and regulations regarding matches and referees, it is somewhat vague and hard to judge.  Because of this, the majority of nitō practitioners only use the short shinai for defense.

            Difficulties in nitō kendo popularity growth

            The development of nitō kendo to a large scale has been hindered by historical reasons, such as the student ban and the late and difficult to judge  regulations. But even today, there aren't many practitioners, and it's generally regarded as a negative deviation from the traditional chūdan stance. There are many obstacles for someone wanting to use nitō, such as the scarcity of two-sword fighting  instructors, the general negative view on nitō, and the skill requirements of effective usage. Because nitō uses the long shinai in a jōdan stance and the short one in a chūdan stance, it is necessary to develop physical muscles that would allow one to efficiently wield the weapons in each arm. Being also a more complex way of fighting, it isn't suitable for beginners, but more to practitioners that have already spent some years training in chūdan. Going straight to nitō is heavily frowned upon. Nishikubo Hiromichi, an influential kendo practitioner and politician of the  Shōwa era, took a more radical view and considered all one-handed techniques should be banned. He argued that using one-handed techniques impede the accumulation of the spirit and that one should not begin training with wielding a sword in one hand, but progress through training normally, until reaching a level where one-handed techniques can be used properly. He also criticized the motion of only swinging the sword without following up with the body, and compared it to a general that orders his soldiers ahead, but remains behind. Even though nitō is also a product, albeit a smaller one, of traditional swordsmanship, the fact that it's being considered more as a negative deviation from the ittō chūdan stance than as an individual style can be attributed to the reputation it had among the students at the beginning of the Shōwa era, and to the fact that it may encourage bad habits for practitioners that aren't sufficiently skilled in ittō chūdan beforehand.

Source(s): Musashi Kai

Miyamoto Musashi's two-sword style

Inspiration for using two swords

There are many theories about how Musashi came to use two swords in his style. His father, Munisai, was a master of various martial arts, including the use of jitte. It is believed that he taught Musashi various combat styles, so Musashi's first impressions on the martial arts as a boy must have come from his father's teachings. One way to use the jitte in combat was to pair it with a long sword, and use it to parry the enemy's attack, then strike him with the sword. This theory is endorsed by a story found in the Tanji hokin hikki manuscript, that describes how Musashi left his home after an argument with his father. He criticized his father's jitte technique, and Munisai, in anger, threw a dagger, then his short sword at him, upon which Musashi dodged both weapons and fled the house. This story can also serve as a basis for one theory which holds that throwing the short sword like a shuriken was one of the techniques that Musashi taught later in his Niten Ichi-ryū style.

Another possible inspiration is believed to be the drumstick movement of taiko. As a child, Musashi had the chance to observe the rhythmic movement of the two drumsticks at the Aramaki, or Sanomo shrine, a shinto shrine in the Miyamoto village.

Without ignoring how these experiences must have influenced Musashi in using two swords, I consider his combat experience as the primary factor for his choice of dual wielding weapons. The historical records of many of his duels, including his most famous one, against Sasaki Kojirō, describe him using a single sword. But in The Ground Book section of his treatise, Musashi advocates the use of the long and short sword for fighting against a large number of enemies:

                        It is better to use two swords rather than one when you are fighting a crowd,                                        and especially if you want to take a prisoner.

He also explains about the best use of the short sword, according to the environment:

                      The best use of the companion sword is in a confined space, or when you are                                         engaged closely with an opponent.

These statements hint at the fact that the effective use of the two swords has been tested through his own experience from his many duels. He found the use of two swords beneficial in various circumstances, as dictated by the environment or number of opponents.

Duels where Musashi fought with two swords

Although few, there are descriptions about some of Musashi's duels where he used two swords. One such duel was against Shishido, a master of the kusarigama. During the fight, Shishido arrested Musashi's sword with the chain, but then Musashi threw his wakizashi and killed him. From this story it can be surmised that Musashi was indeed adept at throwing weapons.

Another duel was the one against Miyake Gunbei, when Musashi used two wooden swords, one long and one short. He restrained Gunbei's sword by combining his two swords into a gassho position,  and kept him in check, before eventually winning by parrying one of his blows with the short sword in his left hand and stabbing Gunbei on the cheek with the sword in his right hand.

This way of fighting by using the two swords like a scissors against the opponent's sword was also mentioned in the description of a match held at Tokugawa Yoshinao's request, when Musashi demonstrated his style by fighting against a swordsman from the Owari clan, and nullified all his attacks with his two swords, while leading him in circles around the dojo and not initiating any offensive action himself.

And yet another use of two swords in a match was against lord Matsudaira Izumo no kami Naomasa, who wanted to test how effective Musashi's style really is, and also had to admit defeat against him.

Two swords in the Yagyū Shinkage-ryū techniques

It is interesting to observe the fact that in the Illustrated Catalog of the Shinkage-ryū Martial Arts, there are some techniques that deal with opponents wielding two swords: the korandome (opponent has a short sword in his left hand a long sword in his right hand), and the subete koran uchimonodome (opponent holds a long sword in his left hand and a short one in his right hand).

 So, even though Musashi was the most famous practitioner and founder of a two sword style, another kenjutsu school also recognized the need to know how to fight against an enemy that is wielding two swords.

Source(s):
The Lone Samurai: The Life of Miyamoto Musashi
The Book of Five Rings
The Life-Giving Sword: Secret Teachings from the House of the Shogun

4 types of commanders who ruin themselves - Kōyō Gunkan

The Kōyō Gunkan is a military treatise of the Takeda clan, one of the prominent clans of medieval Japan, best known for the military exploits of the prodigious general Takeda Shingen. This book was completed by Obata Kagenori, a vassal of the Takeda clan, and it records in detail historical battles of the Takeda, military strategy, army organization, and other aspects pertaining to the bushido and the proper comportment of a samurai. Inside there is a section about the 4 types of commanders that bring ruin to their country and clan, which I summarized below:

The foolish commander. This is the selfish ruler who day in and day out indulges in pleasures and festivities, like trips, moon-viewing parties, hanami, and any other eccentricities that catch his fancy. He devotes himself solely to entertainment, and even though he may take up martial arts on a whim, he can't seriously practice them because his heart always drifts to one thing or another. Many flatterers gather around such a lord, while those willing to remonstrate with him grow fewer. If he were wise, he would know his abilities and recognize flattery when praised for something he isn't good at, but he gets carried away by compliments and is oblivious to right and wrong. This type of commander attracts many sycophants, while good men leave from his employ. The retainers who advance in position thanks to flattery speak ill of good retainers and spread lies to boast of their achievements, even though they haven't achieved anything by 30 or 40. The most representative example given for such a general is the son of Imagawa Yoshimoto, Ujizane. Instead of heeding the council that had served his family for successive generations, he only listened to and relied on a man named Miura Uemon and his connections, bringing the wrath of the Mikawa samurai upon his family.

The too clever general. He is prone to fits of pride or depression. Such a lord is thrifty with paying his retainers, who have to resort to taxing the peasants for their livelihood. Being confident in his cleverness, he doesn't listen to advice, or when hearing the opinions of someone knowledgeable about things, he nods approvingly, pretending to understand. If victorious in battle, he takes all the credit, ignoring the contribution of others. If there are capable men among his chief retainers, he looks at them with suspicion. A good general would acknowledge the achievements of his men and would praise them accordingly, and by doing so his men would grow braver and more loyal. The example given for this type of general is Takeda Shingen's heir, Yoshinobu. At the battle of Kawanakajima, he openly criticized his father's strategy, eventually rebelling against him, and being forced to commit seppuku.

The cowardly general. Such a lord is suspicious towards his retainers, promoting those who flatter him and treating coldly those who would remonstrate with him. He doesn't know the ability of his men, and because he is oblivious to duty, his men seek better employment. He flees from battle and is envious of others, trying to thwart them from success. The example given is of Uesugi Sadamasa of the Oogigayatsu family, who grew suspicious of his retainer Oota Doukan, who proved capable in his assignments. Sadamasa had Doukan assassinated, and because of this, he lost many retainers and became enemies with Uesugi Akisada of the Yamanouchi family. He died when he fell from his horse when crossing a river to attack Akisada.

The overly strong commander. He is confident, quick-witted, eloquent in speech and wise. Because he despises weakness in everything, including words, his retainers can't properly communicate with him, and he takes a liking to those who speak only bold and strong words. Such a lord wants to appear stronger than his predecessors, so he acts in a high and mighty manner. His men fight to the death over any minor trouble, while those who hold their lives dear feign illness so that they can be exempted from military service. Shingen's son, Takeda Katsuyori is given as example. Being the son of such an accomplished general, he wanted to surpass his father. In search of a glorious victory that would propel him forward from his father's shadow, he fought recklessly and was defeated, bringing destruction to his clan.

Takeda Katsuyori

Source(s): 武士道の名著 - 日本人の精神史

Lycurgus - the maker of Sparta

Sparta's discipline and military excellence are well known throughout the world. But the values that have come to be closely associated with the Spartans originated in the laws and constitution attributed to Lycurgus, the founder of the famous Spartan lifestyle. So little is known about him that he may be a legendary figure more than a historical one. However, ancient historians such as Plutarch or Xenophon have investigated lineages and time periods in which to place him.

Lycurgus emerged in a time of chaos and disorder in Sparta. His elder brother who was king, had died and left behind a pregnant wife. Lycurgus acted as king but was ready to serve as a guardian for the rightful heir, should he be a male. But his brother's wife secretly sent him messages that she would abort the baby if he married her. He pretended to accept this plan, but told her that rather than risk an abortion, she should just give birth normally and he would dispose of the child. But when the time came, he sent guards and observers to witness the birth and bring him the child, if it was a boy. And so, when the baby boy was born, Lycurgus presented him to the other citizens as their king, and they named him Charilaus.

The family of the widow sought revenge against Lycurgus, by spreading lies that he wished to steal his nephew's throne. Although the people were devoted to him because of his conduct and high morals, he decided that in order to be clear of any suspicion, he would leave the city until his nephew grew to adulthood and had a son of his own.

Reforms

In his travels, he went to Crete, studying the laws and government there and making note of what was positive in them, so that later they would be adopted into Sparta. Then he went to Asia to compare the luxurious and extravagant lifestyle found in Ionia with the frugal one he had seen in Crete. When the Spartans summoned him back, missing his leadership and guidance, he stated his intention of changing the existing laws with new ones that would improve the order and virtue of the citizens. So he went to the oracle of Delphi and returned with the answer that his constitution would indeed be the most excellent of all. And so, his reforms began. He instituted the 28 Elders in a sort of middle position between the kings and the people, so that neither side would have absolute power. When an Elder died, he was replaced by a man over 60 who was considered the wisest and most excellent of the candidates. The election occurred by having the candidates walk in the assembly in a predetermined order, and shouting to show approval. Nearby, some chosen arbiters were locked in a building where they could only hear the outside, and recorded who had the most and loudest shouting in the order of appearance. The winner was praised and honored by the rest, and offered a meal as a sign of respect. Only inside his mess he was treated as usual, with the exception that he received a second meal, which he then offered to the woman among his female relatives that he esteemed the most, and she was then congratulated by the other women.

He also convinced the citizens to redistribute the land between themselves, so everyone would have an equal share of property, and competition would be in merit, instead of wealth.

One of the most important changes he effected, in order to eliminate greed, was to ban gold and silver currency, replacing it with massive iron coins too heavy and large to be hoarded and with no additional value. Thus luxury was eliminated, because no foreign merchandise or crafts would be exchanged for the unwanted currency that had no value outside Sparta. Further, he sought to eliminate all extravagance and immoderate consumption of food and drink, by creating the system of common messes, where all citizens would gather and eat the same frugal meals. Each member had to contribute a share to the mess every month.

To protect Sparta from negative influences and bad practices, Lycurgus banned foreigners from entering the city and restricted Spartans from travelling abroad. These measures were meant to avoid the exposure to the vices that affected the outside world, such as greed, luxury, self-indulgence or laziness.

Lycurgus was a living embodiment of the values he wanted to instill in Sparta. He led an austere life, was always engaged in some work to develop his character or the betterment of Sparta, and showed compassion even to those who wronged him. There is a story about some disgruntled citizens who attacked him because his laws would eliminate all the advantages of the wealthy. Among them, a youth who struck him in the eye with a stick and blinded him. Instead of running, Lycurgus stood his ground, causing them to feel ashamed of their actions, and so, they gave him the youth, called Alcander, for punishment. But Lycurgus instead took him as his servant, and turned him into a lawful and responsible man.

After establishing his laws and constitution, Lycurgus gathered the assembly and told them that he will consult the oracle at Delphi and inquire if the gods approve of his laws. The Spartans were happy to hear that and encouraged him to go at once, but he first had them swear they will abide by his laws without exception until he returns from Delphi. Having their oath, he went to the oracle and received the answer that his laws are excellent, and Sparta will benefit greatly by adhering to them. He had the message written down and went to Sparta, but decided that he will not return there, so the Spartans would remain under the oath they swore to him. So he chose to commit suicide by starving himself to death, and ensure that his constitution will remain unchanged and endure in the future. He requested that his body would be burnt and his ashes scattered in the sea, so that his remains couldn't be returned to Sparta, and thus release it from the oath of obeying his constitution.

Source(s): On Sparta (Penguin Classics)

The most famous Japanese swordsman - Miyamoto Musashi

Without a doubt, Miyamoto Musashi (1584?-1645) is the most famous of the samurai of Japan. Author of the widely read strategy classic, The Book of Five Rings, and founder of the Niten Ichi-ryū two-sword style, Musashi has an undefeated record of over 60 duels. He also participated in 6 major battles. His legendary military exploits and remarkable insights that he passed on through his book aren't his only notable traits. He led a unique lifestyle, very different from the other samurai of his era, and he showed mastery in the art fields as well, in particular ink painting and calligraphy, even though, as he claimed, he never received instruction in those arts.

It is believed that Musashi learned martial arts from his father, Shinmen Munisai, a master of the Tori-ryū sword style, and also of jūjutsu and the jutte. The relationship with his father was a cold one, and after an incident between the two, he eventually left his home.


First duel
At 13, he won his first duel, against a samurai called Arima Kihei, a practitioner of the  Shinto-ryū swordsmanship style. Even since childhood, it is said that Musashi's stature was much larger than the average height of the Japanese men of that time. Arima Kihei had been searching for opponents, by placing a challenge sign, that Musashi vandalized, and then he fought Kihei and beat him to death.

Musashi also participated in the famous battle of Sekigahara, which finally decided the unification of Japan and the end of the civil strife. However, he was on the losing side, and after the battle, he probably retreated to the mountains to escape the death reserved for battlefield stragglers, and continued his sword training.

Bringing down the Yoshioka school
The Yoshioka school was a famous swordsmanship dojo in Kyoto, run by the Yoshioka brothers, Seijūrō (the eldest) and Denshichirō (younger bother). Both were excellent swordsmen, and Musashi naturally sought to challenge an opponent as strong as Yoshioka Seijūrō. In his duel against Seijūrō, Musashi used a wooden sword and defeated him with a powerful blow, but Seijūrō's disciples saved him and carried him to safety. Unable to withstand the humiliation of being defeated by an unknown country samurai, Seijūrō later abandoned the sword to become a Buddhist priest.

 To redeem the honor of the Yoshioka, Denshichirō challenged Musashi, but he was killed in the duel. After this, the disciples of the Yoshioka school plotted revenge against Musashi, and used Yoshioka Matashichiro, the 12 year old son of Seijūrō, as a lure, to bring Musashi to a third duel, at the Ichijoji temple, on the outskirts of Kyoto. Their plan was to assassinate Musashi, having assembled more than 70 men to wait in ambush for him. But he had arrived earlier and noticed their intentions, so it was them who were taken by surprise when Musashi suddenly jumped among them, killed Matashichiro, and then used the advantage of the terrain and his two sword style to cut them down, keeping them confused and leading them where they would be at a disadvantage. Few escaped with their lives, and this crushing defeat signaled the end for the Yoshioka school of swordsmanship.

The spear wielding monks of Hōzōin
After finishing with the Yoshioka, Musashi went to Nara and fought against the fabled spear technique of the Hōzōin monks, emerging victorious once again. 

Facing the kusarigama master Shishido Baiken
Around 1607, Musashi faced a skilled wielder of the chain and sickle, Shishido Baiken, whose disciples also witnessed the duel. When Musashi killed Baiken, the disciples attacked him, but were quickly put to flight by Musashi's two-sword style.

The duels against Musō Gonnosuke
Musō Gonnosuke was another wandering swordsman, an arrogant samurai who reputedly wore an embroidery on his clothing that proclaimed him the "greatest martial artist in the realm". He came to Musashi and challenged him to a duel, which Musashi won with a single blow of a wooden stick. Gonnosuke was humiliated and he retreated to the mountains to meditate on his defeat. He eventually developed the Shindō Musō-ryū style of wielding the staff (jo), and fought another duel against Musashi, which ended in a draw (the only one in all of Musashi's duels).

Sasaki Kojirō - the Demon of the Western Provinces
The strongest opponent that Musashi faced in his most famous duel was Sasaki Kojirō. He wielded a very long sword, known as the Drying Pole, and had developed a lightning-fast technique called tsubamegaeshi (swallow reverse cut, inspired from the movements of a flying swallow). Their duel happened on a small island which is now known as Ganryū-jima. Musashi arrived late to the duel and holding a wooden sword (that he carved from an oar, according to some sources). Enraged by Musashi's attitude, Kojirō supposedly threw his scabbard in the sea, prompting Musashi's famous words "You’ve lost, Kojirō. Would the winner throw away his scabbard?"
They exchanged blows and Kojirō nearly managed to cut Musashi, but it was him who was struck and killed. This marked the end of the duels where Musashi killed his opponents.

Musashi preferred the wandering lifestyle of a ronin, instead of the more traditional practice of settling down to server a lord or opening a dojo. Nevertheless, he did take disciples and took residence in his later years with the Hosokawa clan in Kumamoto. He frequently retreated to the Reigandō cave, where he wrote the famous strategy treatise, The Book of Five Rings, which explains the teachings of his style. He died in 1645, possibly from stomach cancer.

Musashi's pragmatic teachings and nonconformist lifestyle set him apart from other master swordsmen of his era.  His legacy continues to this day, in the form of his book and swordsmanship style. 

Source(s): The Lone Samurai: The Life of Miyamoto Musashi