site is intended as an introduction to the Japanese martial art of Kendo,
either for the simply curious, or those actively looking to start.
The "gist" of kendo can be summarized in the pithy phrase "ki ken tai icchi," the characters for which are above. It's the semi-official motto of kendo, because it encompasses the entirety of what determines a succesful strike and what a kendo practitioner (kenshi or kendoka), trains for. Essentially, ki ken tai icchi is the entire point of kendo, and it's what separates a kendoka from someone simply swinging a stick around until they hit something.
Unfortunately, the first character, ki, is also the hardest to explain. There are two explanations for the meaning of ki -- a scientific explanation, and a spiritual one. In the interest of fairness, I will cover both. I promise the other characters' explanation will be much shorter.
1) Spiritual Explanation
2) Scientific Explanation
Tai simply means "body." In this case, it means your body must completely commit to every strike you make. There is no lightly dancing around in kendo. When you swing for a target, your body must charge forward with 100% commitment and no hesitation, and you must follow through with full momentum. You cannot timidly strike in kendo.
Finally icchi means "as one," or "in harmony." As the final part of the puzzle, succesful kendo technique incorporates proper ki, proper handling of the sword, and proper movement of your body all acting in unison. If any of these is off, the strike will not count. This is what separates real kendo from the rest. It is not something that can be "thought about," but something that must be slowly learned through years of practice, until you no longer have to think about it.
The kendo uniform itself is two pieces, the keikogi (or just gi,) and the hakama. The keikogi is similar to the tops of gi's for other martial arts, except made of a thick quilted material designed to provide added protection from shinai strikes. The sleeves only come down to just past the elbows to accomodate the gloves. The colors of kendo are indigo (a deep navy blue, almost black) and white. These are the only colors allowed for the uniform. Traditionally, both keikogi and hakama are indigo but some will wear a white top or a black hakama, and some even wear white on white, although this is rare. Indigo is the color of Fudou, The Immovable, the Buddhist god of violent justice and patron saint of traditional samurai. It is used today just out of tradition.
The tenugui or hachimaki is a headband or bandana tied around the head and worn underneath the helmet. It both absorbs sweat, and keeps your hair out of your eyes. There are no regulations governing colors or what is written on a tenugui, so they are the most personal part of a kenshi's uniform. Usually they have some kind of personal philosophical phrase written in Japanese. Sometimes they are gifts given to visiting students, or given out as promotional items by kendo equipment stores.
The good news is, all legitimate kendo in the world is regulated by the same organization, the International Kendo Federation, (IKF or kokusai kendou renmei) which is in turn governed by the All Japan Kendo Federation. (zen nihon kendou renmei). Kendo has traditionally always been free, and the IKF and JKF try and keep as close to this as possible. Kendo instructors are almost always volunteer, and make no money personally for their time. Because there is no financial incentive involved, many people find kendo a refreshing change from the highly commercialized martial arts that are so prevelent today.
Because there is no way to afford rent, kendo is usually done at a public facility donated for use, such as a Buddhist or Shinto temple, Japanese cultural center, or college gymnasium. Some colleges will charge slight fees for the use of their facilities, which can raise the price slightly at some dojos. The All US Kendo Federation (AUSKF) also charges $40/year to keep its members insured in case of legal action. (A downside to living in a country full of people who sue.) There are also local state dues, which vary from state to state. Some charge as little as $5/mo, others as much as $40. Regardless, it is still far cheaper than most martial arts today.
The equipment, unfortunately, is another matter. Shinai cost anywhere from $15 to $70 depending on the quality of the bamboo. The more expensive shinai tend to be oiled and sanded to withstand use. Shinai do break and need replacing every few years. A shinai is the bare minimum needed to start practicing kendo, although some dojos will have shinai to loan beginners. There are also carbon fiber shinai, colored to look like bamboo, which do not break and require little care. They can run up to $200 though, and many complain that they lack the traditional "feel" of bamboo.
The gi and hakama are not necessary for a beginner, however many try and buy them as soon as possible so that they can get used to them quicker. Gi and hakama are either made of polyester or tetron for the cheaper versions, which require less care, or 100% cotton with natural hand dye for the expensive versions, which require more care but look better. Low end gi and hakama typically run $50-$150 for the set. Extremely high end sets can run $500 or more.
Bogu is expensive, but American dojos usually do not allow beginners to wear armor for quite awhile anyway, to prevent injury. Sadly, many people starting kendo do so because of something they saw on television or in a movie, and if they were allowed to wear armor from the beginning they may end up seriously injuring themselves or others. This means a beginner doesn't have to worry about buying armor for quite awhile. Entry level bogu sets typically run $150-250 and will last the life of the kendoka with proper care. High end sets can run thousands of dollars, and extremely high end sets, such as those used by the top sensei in Japan can run $10,000 or more.
Online Kendo Equipment Stores:
Kendo Ranking System
There is no outward display of rank in kendo. Everyone wears the same uniform, with the same colors. There are no colored belts or patches. Some people find this a welcome relief from the belt-oriented world of other martial arts. Others find it frustrating to not have anything physical to show for your effort. It is still usually very easy to judge what rank someone is by watching them fight, as well as how they dress and act.
Kendo uses the kyu/dan system. At the lowest rank is 10th kyu, which procede upwards to 1st kyu. The next step after 1st kyu is 1st dan, or shodan, equivalent to "black belt" in other martial arts. The dan ranks then extend upwards to 10th dan. In practice however, most adults start at around 4th to 6th kyu. There are no more 10th dans alive. Naturally, you cannot raise someone to a rank higher than your own, and no 10th dans were promoted before the rest of them died out. Therefore there will never be another 10th. Similarly, there are only a handful of 9th dans left in the world, and it appears likely the same thing may happen with them.
Traditionally, there were no kyu ranks, and you were mudan (unranked) for many years before you recieved 1st dan. That is why 1st dan is still called shodan, or "beginner's rank."Kyoushi, renshi, and hanshi are honorary ranks awarded to very high level kendoka, for superb skill as well as having a good character and helping the development and practice of kendo.
Dojo Etiquette and Respect
There are a number of traditions and rules governing proper respect whenever inside a kendo dojo. Even if the dojo is a school gymnasium, or a run down temple, whenever keiko (training) is in session you treat the building with full respect.
Seiza is the proper way to sit in a dojo. From a standing position, kneel on to your left foot, keeping your back upright. (This is tradition, because until your right foot is pulled back you can still draw a sword.) Then pull your right leg back, and sit back gently on your legs and heels, with the tops of your feet on the floor. Your toes should touch in back, and your knees should be slightly spread in front. For a non-Japanese, this is often extremely uncomfortable at first for any length of time. You will slowly get used to it. Your hands should rest on your knees or upper thighs and your back should be straight, not leaning forward to try and relieve the discomfort -- you'll get used to it with time. The shinai is placed at your left side, string down, handle facing forward, crossguard (tsuba) in line with your knees.
The bow, or rei, is done from either a standing position with your back straight, hands at your sides, or from seiza. When performing a seated rei, place your left and right hands in front, forming a triangle with your thumbs and the rest of your fingers. Then bow towards the triangle, keeping your back straight and your butt down. Hold for a brief second, longer to show added respect, and then come back up.
Kendo Technique and Basics
How to Grip the Shinai
You do not hold a shinai like a baseball bat. Do not grab it from the sides in a full fisted grip. Instead, hold it loosely from the top, so that if you look down on the handle from above, the gab between the thumb and index fingers on each hand will form two V's lined up with one another down the top of the handle. Your pinky and ring fingers should be providing most of the pressure, and your other fingers should be only lightly gripping the handle.
Your right hand goes on top, all the way up under the crossguard. Your left hand goes at the bottom, all the way down until there is little to no white showing past your pinky and ring finger on your left hand. This might seen like a very wide grip at first, but it provides the greatest amount of angular leverage for control and speed. No, katanas are not used one-handed, no matter what you see in movies. A katana is too heavy for one hand unless you are very big and extremely strong, and even famous dual-wielding swordsmen such as Miyamoto Musashi had to use a lighter wakizashi instead of a second katana in the left.
The shinai grip is identical for right-handed and left-handed kenshi alike. Left-handers may be a little worried about this, but the kendo swing is so unnatural at first that no one has an advantage. It will be just as akward for you as it is for the righties, so you'll both learn at the same rate.
Valid Targets in Kendo
There are only certain valid targets in kendo - those that would cause immediate incapacitation or death if they were struck with a real sword. Targets such as the shoulders, legs, and upper arms are not valid because they are not necessarily lethal or incapacitating.
All targets are struck with a slashing motion except for tsuki, which is a thrust to the throat. However, a thrust to the throat even with a shinai can be extremely dangerous and potentially fatal. Beginners do not learn tsuki until much higher level.
Note that the do protector only covers the sides from the lowest rib to the hips, and the unprotected area of the ribcage itself under the arms is not a valid target. It is quite hard to slash through someone's ribcage, however a strike to the soft sides of the stomach will be immediately debilitating.
The Force of the Swing
It seems unnatural at first, but the strength and power in a swing comes from your left hand, not your right. Your right arm should provide little to no force to the swing. Your left arm drives and pulls the shinai, and your right hand simply adjusts the angle and position of the tip, and also stops the swing. Perhaps the most common mistake of beginners is to use the muscles of the right arm to swing. Ask any golfer what happens if you try and use the muscles of your right hand in a golf swing. The swing will go wild, you won't hit your target, and you'll hit very hard with no self control. This not only looks terrible, but will piss off your opponent as well. A trained kenshi can swing with full force in the left hand, and use the right hand to bring the tip to a perfect crisp stop an inch from their target if they are so inclined.. You cannot do this if you're swinging with your right hand.
If you want to cut a piece of meat, you don't grab a steak knife and try to push down on it as hard as you can. The only way to cut is to slice neatly with the correct angle. A proper kendo swing combines the power of the left hand with the precision of the right to include both strength and precision without sacrificing either.
Sonkyou - Starting a Match
While all martial arts have a bow before starting the match, kendo has a slightly longer process. From a distance of 9 paces, both kenshi face one another and perform a standing bow, with the shinai held naturally down in the left hand, "blade" facing upwards. When the judge gives the go-ahead to begin, the shinai is brought to a position on your left hip in the position where a katana would normally be sheathed. The thumb comes up to cover the crossguard (tsuba).
Both kenshi take three steps forward, drawing the shinai in a large arc over the head and down towards chuudan no kamae while very slowly crouching down into a balanced position on the balls of both feet. If the distance is correct, the tips of the shinai will just barely touch. A properly executed sonkyou is beautiful to watch, and you can often tell someone's rank just by their sankyou.
When the judge calls hajime, both kenshi stand and shift into guard positions, and the match begins.
When the match is over, both kenshi return to the middle, crouch back in to sonkyou, and the process is reversed. The shinai is "sheathed," the opponents slowly stand, walk backwards five paces, (because people tend to naturally take smaller steps to cover distance while walking backwards), drop the shinai back to their sides, and exit the arena.
Chuudan no Kamae
Chuudan no kamae means "center guard" or "middle posture" and is the basic guard or ready position in kendo. Although it is not particularly flashy or impressive to look at, it was developed over centuries of trial and error and is the strongest balance of offensive and defensive ability.
Your right and left foot both point foward, with the right root in front. Your left foot goes behind, but close enough so that if seen from the side, the toes of your left foot and the heel of your right foot would be in line. The heel of your left foot is raised slightly with weight on the balls of both feet. Your weight should be divided relatively evenly, but with more weight on your front foot than the back. (If you are caught with your weight on your back foot, your balance is dead and you will probably get smacked a second later.) Regardless, it should be equal enough that if you raise your right foot, you will slowly tip forward and fall, and the same for your back foot. Your right leg should be very slightly bent, and your left leg will naturally be mostly straight, but not locked.
The shinai should be held naturally, with proper grip, with the left hand about one fist away from your body. The blade faces down. (Meaning the string is up.) Your shoulders should face forward squarely with the shinai facing right down the middle of your body. The tip should be aimed directly at your opponent's throat.
From chuudan, your shinai is approximately equal distance from all valid targets on your opponent. The position and balance of your feet makes it easy to leap forward very quickly or slide backwards if necessary. More importantly, as long as you keep centered with the tip squarely pointed at your opponent's throat, you are virtually invincible because the length of the shinai keeps them precisely too far away to hit you. By merely turning your entire body to keep centered on their throat, they cannot get within range. The angle of the shinai protects your wrists, your arms prevent any strikes to the body, and you have enough time to block any attempts to your head or throat. Of course, because your opponent is also in chuudan, that means you can't hit them either.
Other kamae positions:
There are other guard positions as well, however only one of them is ever regularly used, and even that is rare.
Joudan no Kamae - (Upper Guard/Stance) The feet are reversed, with the left foot forward and right leg behind with the heel up. Almost all weight is on the front foot. The shinai is held overhead at an approximately 45 degree angle to the horizontal, and angled slightly so the tip points slightly back to your right. This is an extremely offensive position, sacrificing almost all of your defense. It also leaves you very vulnerable to do or kote strikes. It also severely limits which targets you can feasibly hit. Its strength lies in the fact you already have half of your swing completed, and the only part left is the downward slice. This gives you a time advantage over your opponent if you are trying to strike men, and it is often impossible to really block a men strike from joudan - instead it is better to attack someone in joudan immediately before they can swing.
Joudan can be done either with left foot forward (hidari joudan, the most common) or with the right foot forward (migi joudan, rare).
Gedan no Kamae - (Lower Guard/Stance) This is a purely defensive position. The feet are in the same position as chuudan, except the tip of the shinai is lowered and rolled slightly to the right until it is at the same height and in front of your right knee. This is never used in actual matches except to briefly taunt your opponent into attacking you.
Hassou no Kamae - (Eighth Aspect Stance) The body position is the same as joudan, with left foot forward, except instead of held over the head, the shinai is held vertically next to your face, with your fists by your right cheek. This was traditionally used for very heavy weapons which could not be held in joudan or chuudan for any length of time without tiring. It is sometimes used by high level kenshi, but only as a very brief fake on the way to a full strike.
Waki Kamae - (Flanking Stance) The most exotic position. The feet are reversed like it joudan or hassou, however your body is turned slightly to the right, and the blade is held at your right hip with the tip pointing behind you, sharpened edge up. Your body obscures the blade from view from the front. Almost entirely worthless in modern kendo, although still used in one of the forms.
You might be tempted to skip over this section, but it may be the most important part of this whole page. Unless you know how to step, and how to move your feet correctly, nothing above your feet will move right, including your hands. Proper kendo starts with your feet. They are the source of your momentum, and the principle part of the tai in ki ken tai icchi.
Kendo footwork is designed to allow movement in any direction without putting your feet in a position that compromises balance. If you walk with alternating steps, there is a brief moment where your feet are right next to one another as one crosses by the next. In this brief moment, if you are pushed in any way, you will fall over.
Instead, kendo uses sliding footwork and non-alternating steps. To move forward from chuudan, the right leg slides forward and the left left then slides up back to its original position, leaving the heel raised the whole time. To move backwards, the left foot slides back and the right foot then slides back to meet it. This way, you maintain balance and potential power if someone pushes on you during a step. To move right, the front leg slides right, then the back. To move left, the back foot slides back, then the front. You are never caught off balance with your feet next to each other.
Trained kendoka are capable of sliding across the floor very very quickly using only this sliding footwork, called suriashi ("sliding feet"). So quickly, in fact, that they appear almost to float across the floor without actually stepping at all.
Kiai is "meeting ki," or a verbal challenge in the form of a yell or scream. You cannot do kendo without proper kiai, because kiai forms the basis of the ki in ki ken tai icchi. Good kiai does not come from your chest as though you were yelling normally, but is an explosive yell that comes from deep in your stomach as loud as you can. Do not try and "say" the yell, with your vocal chords, but rather release all of your breath in an explosive discharge of energy as though you were trying to flatten your opponent with just your voice alone.
A good kiai can actually win a fight by itself, and I have personally seen it happen many times. A good, proper base explosion of verbal energy often provokes a involuntary flight response even if you see it coming ahead of time. If your own ki and self-confidence is not strong enough to meet it, it can cause you to hesitate slightly for a fraction of a second, or flinch involuntarily (mentally or physically), which is all your opponent needs to win the point.
Kiai is mandatory when you land a strike, and the word that is yelled is the target you were aiming for. However, you can also (and should) use kiai to establish superiority at the start of a match, or to try and throw your opponent off guard.
Maai - Range
The length of the shinai and the chuudan no kamae position establishes a set range from which you can hit your opponent. A taller person will have a naturally longer reach, but an ability to jump long distances forward also extends your reach. Managing range or distance, called maai, is absolutely essential for a kenshi. You must know from how far away your opponent can strike you, and how far away you need to be to hit them back. It varies according to age, sex, strength, ability, build, shinai length, opportunity to strike, etc. It cannot be taught but is rather learned through practice.
The difference in range between kendoka sometimes varies by as little as an inch or two, but a good kendoka can manipulate maai perfectly to take full advantage of it.
Standard maai is called issoku ittou no maai, or "one step one strike range." For two kenshi of equal height with no extraordinary speed or strength, this is the range pictured above, with shinai barely crossed at the tips. This is the outer limit of range for most people. From this position, any target can be struck if you take one step forward, but taking that step also puts you within your opponent's striking distance. Most kenshi will stay at this range, moving back and forth or circling while attempting to somehow break the other person's chuudan guard, and then move in with one step to strike a target.
Zanshin - Follow Through
Zanshin literally means "remaining heart" or "left over soul," or what have you, but that doesn't explain it very well. More accurately, zanshin means that after you strike a target, you are completely mental and physically prepared to strike again or immediately defend yourself if necessary. This is absolutely critical - without showing proper zanshin, the point does not count.
In kendo, after attempting a strike, the kenshi ideally charges past their opponent (to the right or left) using suriashi footwork. This is quite natural if you already have proper form, because at that point you have so much physical and mental momentum that it's quite hard to stop. Once you have moved past your opponent and far enough to be out of range again, then you turn and prepare for another attack.
This is important because in a real sword fight, there is no guarantee that a strike will immediately disable your opponent, and you cannot afford to relax physical and mental energy until you are once again far enough away to be safe. The weight and momentum of a katana (as opposed to a lighter 1-handed weapon) makes it impossible to swing with commitment and then immediately defend. Ki ken tai icchi dictates that you must commit 100% to the swing, which means you can't hold back expecting to defend after you strike. The only thing you can do is get past them and out of range as quickly as possible.
If you do not show proper zanshin, a skilled kendoka can easily use the free opportunity to either strike you back, or take advantage of your falling ki to smack the shinai right out of your hands.
Tai-atari - Body Check
Sometimes, if both go for the same strike, neither will hit. For instance, if both kendoka attempt to strike men at the same time, both swings often deflect one another. However, both kenshi still have full forward momentum and commitment, and sometimes they can't go around or past. At this point, both kenshi run into one another and tai-atari, or tsubazeriai, (a "body check") occurs.
During tai-atari, both kenshi are locked with shinai crossed between them, pushing on one another. (And it's always far more intense than what's pictured above.) Both are trying to push the other off center while trying to come back to chuudan themselves. The problem is, the first person to break tai-atari cannot come back to chuudan instantly, and therefore they will leave themselves open. Thus, neither kenshi wants to break tai-atari without somehow covering themselves in the process. This is the only time in kendo where raw physical upper body strength has any sort of advantage.
There are a number of techniques for breaking tai-atari, and striking a target while retreating back to chuudan, called hiki waza.
Kata - Forms
Similar to other martial arts, kendo has a set of forms. One difference, however, is that kendo forms are always done in pairs. They are demonstrations of techniques used for fighting, therefore there is both an attacking and defending side to each form. They are never done alone.
Kendo has 10 forms, each with an attacking side (uchitachi) and a defending side (shitachi), for a total of 20 forms that a kenshi has to memorize. Uchitachi instigates the attack, and shitachi dodges, blocks, or otherwise counters the attack to win.
You do not need to know the forms until you test for 1st kyu, when you'll need to know both sides up to number three. For shoudan, you must know the first 5. 2dan is the first 7, and 3san is all of them.
- My head hurts...
Yes, it's a lot of information all at once. You'll notice that I haven't even explained the mechanics of the swing yet. Not even a men strike, the very first, basic move of kendo. There are so many intricate details to the various swings that I really don't think they can be fully explained in text. Each swing has been refined and designed to provide the most efficient, fast, powerful, and precise movement with the least amount of expended energy. It is the efficiency of kendo that makes it so beautiful to watch, in my opinion. There is very little wasted energy.
The downside is that even something as basic as the overhead men swing has dozens of minor points that can't be explained without pages and pages of instructions. It is both easier, and a whole lot more fun, to learn yourself by joining a dojo in your area. Remember, it's very cheap, and you don't need anything but a shinai to start. (And sometimes they will even loan you that.)
All legitimate kendo dojos in the world are members of the International Kendo Federation, and they all have directories of their member dojos listed online.
Frequently Asked Questions and False Claims
- What's "kenjutsu?"
Before the collapse of the military government in 1867, all sword fighting in Japan was collectively known as kenjutsu. "jutsu" is a word meaning "practical technique," and is used in many different Japanese words that have nothing to do with martial arts. For instance, "fine art" is bijutsu or geijutsu. "technology" is gijutsu, etc.
When the samurai class was abolished, all martial arts were viewed with a certain revulsion by the public at large, which was trying to forget its military history. The myriad sword schools, or ryuu, were shut down by the government, and swords were confiscated from the entire populace. In order to keep the art from disappearing entirely ex-samurai began to condensce the ryuu's into a single system, which they could tout as a martial art meant to expand the mind and build character, instead of a lethal killing system. Thus, kenjutsu became kendo, with the "do" character meaning "path" or "way." Almost all of the former kenjutsu instructors changed to kendo so they would be allowed to continue.
It was the same with other martial arts. Jujutsu became judo, for instance. ("jujitsu" is a western mispelling.)
There are still countlessndojos around the world touting that they teach "traditional kenjutsu." I am hesitant to call them all outright fakes, but the vast majority are simply scams. Ironically though, all of them claim that all the rest are scams except themselves, of course. Before 1867, the country was closed to foreigners, and no samurai would have even dreamed of exporting kenjutsu techniques abroad. Even up until WWII, the art of the sword was considered an intensely Japanese Only thing, and it is extremely unlikely that any of the techniques would have been exported. By the time Japanese martial arts were being openly exported to America following World War II, 80 years after kenjutsu ceased to exist, it is nearly impossible that any teachers of "traditional kenjutsu techniques" would have still been alive.
Regardless, there are countless people who claim to have some distant relation to such-and-such kenjutsu teacher. The point is, calling your martial art "kenjutsu" is an active attempt to associate yourself with an art that officially ceased to exist more than 135 years ago. People may have many reasons for trying to do this, but I will leave that to the reader to decide.
Be extremely skeptical of people claiming to know or teach kenjutsu. Especially if they want a significant amount of money to teach you.
See above. Kendo was formed by teachers and students of every sword school coming together to preserve the art. Therefore, kendo is essentially the amalgamation of all the sword schools in Japan at the time, with modifications over the years to incorporate modern shinai and bogu.
Shinkendo is the brainchild of Obata Toshishiro, a martial artist who believes that kendo has become too mainstream and "sporty." He believes that kendo's use of shinai and bogu to only strike certain vital locations is unrealistic and too far from traditional kenjutsu. He started a new kind of kendo which he calls simply shinkendo, literally "new kendo."
Many kendo practitioners dismiss shinkendo as a fad and empty hype. I will not draw any judgements here because I know very little about it. I have never even seen a shinkendo match, and so I am completely unqualified to pass judgement. If you are interested, their website is here.
Ni tou kendo is a legitimate subset of kendo which uses two swords, a long shinai and a shorter shinai like a wakizashi. It claims to date back to Miyamoto Musashi, however there is no real confirmation of the claim. Ni tou kendo is not a separate school of its own, rather it is a specialization that already very skilled kenshi sometimes choose to learn. For most kenshi, dual-blade style is interesting and fun to watch, but not practical enough to really take up.
It is actually very similar to normal kendo. The right hand blade is kept in chuudan while the left hand is kept in joudan. All techniques and footwork are the same. Typically, the right hand parries or pushes the opponent's blade out of the way, while the left hand swings for the point.
Despite common belief, dual-bladed kendo does not provide any substantial benefits over single-bladed kendo. As long as the kenshi with only one blade maintains proper stance and maai, it doesn't matter how many swords their opponent has, because they'll never get close enough to hit anyway.
Musashi was a ridiculously famous ronin, or "masterless samurai" who lived during the Edo period, during the Tokugawa Shogunate. He is famous for his dual-bladed fencing style, and also for winning over 60 duels during his lifetime. In the last years of his life, he retired to live in seclusion in a cave and wrote the Go Rin no Shou, or Book of Five Rings, (online translation is here,) which was his philosophy towards life and kenjutsu.
Unfortunately, the mythos of Musashi makes it very difficult to know where the real man stops and the legends begin. Books which claim to be the "official biography" are usually anything but. There are very little records dating back from that era. It is known how many battles he won, and the circumstances of each, but anything beyond that is mostly heresay. Reports say that he was a very big man, and that seems consistent with the considerable strength required to use a katana with one hand.
Musashi is famous not just for his superb swordsmanship, but also for being quite intelligent and clever, often winning duels by outsmarting his opponent, rather than cutting them down. He is also famous for being an accomplished painter, poet, and author. Slightly less famous for the fact that he considered bathing to be unhealthy, and did not bathe for most of his adult life.
This is a question that actually comes up fairly often, suprisingly enough. The 16-petalled chrysanthemum is the family crest of the Japanese Imperial Family, gold on red. Kendo and kenjutsu were often considered under the control of the imperial family although this was only technically a formality. This crysanthemum is used in the same situations that the Seal of the United States (the eagle and shield holding olive branches and arrows) is used in America, on money, passports, etc.
During World War II, the imperial government tried to raise nationalist fervor by hyping up the role of the sword in Japanese society. Japanese military officers were given swords stamped with the Imperial Crest, although they were usually cheaply made. Because of this, it is common to see the chrysanthemum sigil on old weapons. Note that you cannot use the sigil on your own, (such as for a crossguard decoration), unless you reduce the number of petals from sixteen.
Iaido is a martial art separate but linked to kendo. Iaido, or battoujutsu, is the art of drawing the sword and attacking simultaneously. It is a predominantly solitary martial art, comprised entirely of forms, however they will occasionally do cutting demonstrations using rolled up and moistened tamami mats.
Iaido does not use the shinai, instead using something called an iaito, which is a practice katana balanced and created specifically to practice iaido.
Many kendoka are also iaidoka, and vice versa. Iaido practitioners wear no armor, but usually wear black on black or white on black, with no indigo anywhere on their uniforms. Some wear striped hakama of many different colors. Usually if you see a kendoka wearing a black hakama with his indigo top, it's because he started as an iaidoka and didn't want to buy a separate hakama.
Not like you see in movies. There is simply no reason to ever spin. You can attack faster, more reliably, with greater strength, and more accurately without spinning. Spinning presents your back to your opponent, which is essentially guaranteed death if they have any skill at all. If anyone tried to spin versus a trained kenshi they would find themselves very quickly annihilated.
Kendo incorporates turns at the end of the strafing movements of zanshin, to efficiently move back to chuudan, but that's basically it.
Images are used from Kendo: The Definitive Guide by Hiroshi Ozawa et al. Images are used without permission, but I'm sure Mr. Ozawa is a very nice kendoka and not the type to sue someone like me. I highly recommend everyone buy the book, because it has 100x the information I presented here.
Other images used from Tozando.com, E-Bogu.com, and the International Kendo Federation.