I'm inspired today by the common thought that "you can't learn martial arts from books" ... or even videos, according to some. Yet, most of us know well enough that there are vast numbers of martial arts books and video materials in the market, and they are usually written or made by, or else feature, highly-credentialed and often well-known expert teachers. Would they do this if it were useless?
That would be at best dishonorable to do, flying in the face of professional and martial integrity.So, let us presume that our respected teachers, seniors, comrades, etc. who have made books and videos do in fact believe that they are benefiting fellow martial artists with their works, and further, that they are correct, as is expected of experts. At the same time, the "can't learn" dictum also comes from experienced people at times, and there is some truth there as well. So, let's try to understand and reconcile them, and then consider how these materials can be used effectively.
For me, the truth of this matter is apparent by looking at it from two sides. First, there is the truth that in order to learn to do something, we must practice doing it. And this is best done under the guidance of a teacher who can observe us and tell us how to avoid mistakes and do it better. Second, careful observation is also a valid way of training, under the right circumstances. We'll look a little more deeply at each one in turn.
Again, the way to learn to do something, or at least to do it well, is to practice doing it. The best way is with the help of a good teacher. Some would have us think that this is the only way. That is not true, since if it was, there would never been any innovation nor progress, and all martial arts would be identical - and far inferior to what we have today. Nevertheless, to learn it is far better - quicker and easier - with a good teacher helping us. With or without a teacher, though, we have to DO it in order to get better at it over time.
Next, we look deeper at mitori geiko, the Japanese term for training by intent observation. In short, this means learning by watching carefully what another does. It may be a teacher, or classmates, or especially in the case of duels and sporting competitions, observing the other party. If someone is injured and cannot physically practice, they can still benefit greatly by attending the dojo and doing mitori geiko.
In fact, one of the modes of traditional training, in which teachers don't explain, but simply demonstrate, and then have students try to emulate what they saw - often called "stealing the technique" uses mitori geiko followed by physical practice.
As I see it, using videos and books is really another form of this same mode of practice! In all cases, you pay attention to what you see, and then try to practice it, to duplicate the technique or exercise.
Still, the best way is to learn under a teacher who does explain and actively helps us to improve, rather than just hoping we'll manage to successfully "steal" the technique. The problem is that without active guidance, whether we are trying to copy an uncommunicative teacher, or a video, or a book, we can very easily miss crucial, but subtle points, or get into bad habits when we don't realize we are doing something wrong.
Now, bringing all these things together, mitori geiko of any sort, including using books, is far more useful and effective if you already have a foundation in actual practice. As such, I would say that, while it is not impossible to learn - as a beginner - from a book, it would be very hard, and the process would have many potential pitfalls. If, however, we have relevant experience and practice, then we can use the information to adjust what we have already learned and practiced.
For example, in my youth, I studied Tae Kwon Do for... perhaps a little under a year, earning several promotions. I have continued, over the years, to occasionally practice the poomse (Korean for 'kata' or forms) that I was taught in that time. Recently, I acquired a book giving one of the newer official sets of forms (the Tae Geuk), which my school did not use, at least not at that time - just before I had to stop going (due to an injury sustained elsewhere) there was talk of the school switching to a new system of poomse. In any case, although they are not the same, there is a strong overlap between the forms in this book, and those I learned years ago. As such, it is not a major leap for me to practice these "new' forms by carefully following the directions and paying close attention to the pictures. Even so, it would be far easier if I were to enroll in a dojang that uses the Tae Geuk forms and get proper instruction. However, if I were a beginner with no experience, it would be far harder to learn these forms from the book, and I would surely make far more mistakes.
In the end, it is again best to learn from a good teacher. If you can do that, do it! If you can't get a teacher, sometimes it is possible to observe classes. This depends on the art and the particular school. Aikido dojos tend to be very open to visitors; some other martial arts, especially certain very traditional ones, tend to be very closed and secretive, not allowing non-students to watch. If you can't watch instruction in person, then video materials are next in usefulness. Finally print materials, books, ebooks and magazines. Again all of these are much more effective if you have experience to build upon, if you already have some knowledge and practice.
And if you are an absolute beginner? It is truly best recommended to join a school or otherwise find a teacher, but if you must try to learn in one of these other ways, involving mitori geiko, I would offer these thoughts: Observe not only the teacher (even if that be a book, etc.), but also, very intently, yourself, your body. Try to feel what you are doing, and to do it with care, attention and precision. No matter what the art, I would strongly recommend first of all carefully learning breakfalls and rolls; that way, you are less likely to be injured if you lose your balance or otherwise fall while practicing other techniques later, and certainly if you have or get a training partner. I've seen some good videos online on how to safely ease into rolls and breakfalls particularly made by practitioners of Aikido and the Russian art Systema. Go slowly, try to pay attention to any subtle differences due to variations in your stance, position and movements. Pay attention to balance and to your center, so that you can maintain balance. Along with this, pay close attention to footwork. And when your situation allows you to get a teacher, do it. ;)
As a proof that it can work, I've read of a number of Aikido dojos and clubs in the US that started with groups of friends training together from the few early books. This was particularly before there were more than a handful of teachers.
As a final note, current technology now allows for even personal instruction at a distance, to some degree, with the availability of video calling. A number of prominent martial artists, such as Stephen Hayes and Jet Li, have started online schools that allow for teachers to periodically evaluate students via video, and doubtless others will do likewise. This new option in training, in effect, combines training-by-teacher and training-by-observation. It will be most instructive to see if it is indeed viable and effective after some time has passed.
