You’ve got a real problem here and it’s that traditional martial arts like Judo and the “street fighting” styles don’t mix at all. Martial arts each come with their own personal philosophies and ideologies, there’s an inherent outlook that changes how a student perceives the world around them as they train. This is why the advice is always to learn one martial art at a time, build a strong base and then expand your knowledge. If the student is presented with two conflicting world views, they will struggle and inevitably become subpar compared to their fellows. This is especially true of Judo, which is a Japanese martial form like Jiu-jutsu and Aikido, which draws its philosophy from Bushido. It’s a disciplined, even rigid, style of training and it requires an unquestioning obedience from its students in the beginning. We simply do, we do not question why. Understanding comes through the process of doing and the answers you seek will be discovered in time, be patient. Patience, acceptance of the natural order, unquestioning obedience to authority, and rigid discipline are going to be an important part of your MCs training in Judo. Traditional martial arts is big on learning the technique first and figuring out/discussing the application later. Thus, the process of learning is much slower though the student arguably turns out the better for it in the end. This doesn’t mean the experience is joyless or all serious, in the hands of a good instructor it’s actually a lot of fun, but it is a completely different and incompatible outlook from conventional street fighting.
Comparatively, training in “street fighting” generally revolves around beating the ever living crap out of each other until there’s only one left standing. The one left standing is a badass. “I’m so tough, I don’t need to train” is the usual refrain. The only time your conventional backyard brawler is going to go out looking for training (or think they need it) is after they’ve been beaten to a bloody pulp. This is where we get characters like Buffy, by the way, where training becomes a means of working out aggression or something they do when they feel they need it instead of a consistent form of self-improvement. A good example of street fighter training is, ironically, Fight Club. The novel actually does an exceptional job of illustrating the sort of mindset that creates. “Street fighting” knife combat training would be to shove a live knife in your MCs hand, kick them into the arena, and have them fight for their life. First lesson: don’t die. End lesson. If they survive: rinse, lather, repeat. No other lessons needed. It’s a high to be sure, but ultimately the actively aggressive mindset will get them into a lot of trouble.
Your MC’s focus is going to be on all the wrong things and they are going to end up seriously confused. Also, subpar and ineffective. A decent, though not entirely accurate, comparison would be Jedi versus Sith. They’re going to have to choose one or the other and they can’t do both at the same time. Finally, much like in Star Wars, the learning curve with the Jedi begins very slow but will rapidly outpace Sith training by the end. Street fighting is ultimately a “feel good” flat progression where Judo is consistent and continual improvement. Modern Judo is a sport form and it doesn’t translate well (straight up) into street combat, but it has been adapted into several different self-defense forms and has a focus in Police (U.S.) hand to hand. Martial arts communities often have close ties to both the Police and the Military, sharing students and knowledge between them. Your MC’s aunt is actually in a good position to hand her niece off to learn real world application and strategy for the techniques she already knows from a professional combatant in the community. (It’s probably a retired or active police officer.) She’d be better served (and safer) learning “knife fighting” from them.
There’s another way to do this and have it all work together without the general confusion. Let me start by talking about martial arts families.
You’ve got two choices with your MC’s aunt for how she started training your MC.
1) When your MC became a teenager, she fell in with a bad crowd. She never really had an interest in the martial arts or her aunt, who is either a distant figure or an inactive one in her life. She knows her in passing, but not much more than that. However, she’s become a problem and her parents want to see her straightened out (especially if she nearly died in an underground knife fighting tourney). They hand her off to this aunt for training, to get her the discipline she needs to figure out her life. In this set up, the aunt is best off as both a Judo master and a burned out cop. She can combine brutal real world practicality with strict discipline and becomes an important mentor figure to our troubled youth, one whose secondary plot is to overcome her own crisis of faith and come out of her shell. It’s a standard movie plot, troubled youth finds sense of purpose while their mentor becomes reinvigorated. From The Karate Kid to Finding Forrester, it’s an oldie but it works really well. Your character starts with street fighting and finds meaning, structure, and purpose in Judo.
2) The MC’s aunt has been an important part of their life for as long as they can remember. Like so many real world martial arts instructors, they served as an active babysitter and began training their niece in the martial arts before they could toddle. By the time she was three, your MC had learned the proper hold position on the gi and could “throw” her aunt across the room. (The aunt did most of the work, but the sentiment is real.) In fact, the MC has many family videos detailing herself as a small, giggling child performing techniques for a live audience. Always the favorite, she’s been held up as a gold standard for other students at her Judo school for most of her life. Martial arts and the martial arts community were part of her life from the beginning, she can’t remember a time before. (Search kids and martial arts, you’ll find plenty of videos documenting this behavior. I will attest to it, I’ve known too many professional martial artist uncles and aunts who do this. It’s free babysitting and daycare for the parents, so they don’t usually say no.) But, martial arts has always been something of a game and a hobby, so much a part of our young MCs life that she never thought to question it. That is, until in an attempt to test her limits, she ran across a street fighting crowd and got her ass handed to her. (A charismatic handsome boy or pretty girl, depending on your MCs sexual preferences should fit in here because this group represents a sexual awakening as well as a philosophical questioning. It’s part of growing up.)
Enter the Crisis of Faith, everything your MC thought was true about herself (her combat proficiency, her sense of superiority, her personal philosophy, etc) has been challenged and she must ask herself if her aunt was wrong this whole time. If her whole life and what she knows to be true about the world has been a lie. (It’s not, but this is the key question we all must ask ourselves as we transition from childhood to adulthood.) Wanting to test your own limits, to navigate the confusing politics and philosophy of application of force, to know if what you’ve learned as absolute truth has meaning and value, to ask “can I really defend myself in a real fight?” is a natural part of learning martial arts especially from a young age. The answer, with traditional martial arts, is actually no. Not because Judo doesn’t has application as a self-defense form but because that isn’t the focus of traditional Judo or even a part the training may cover. This is why she gets beaten, this is why she fails, not because the training itself is worthless but because that’s not what the training was training her to do (it does however lend her the keys to sort her way out of the mess). To get the answers she needs, she’ll have to seek answers somewhere else. This is where the street fighting comes in to present a seductive conflicting philosophy to the one she’s known all her life. “Maybe it doesn’t have to be this hard, maybe I don’t have to be so rigidly disciplined, this feels good. I feel powerful.” (If you’re going to go this route I recommend reading both Fight Club and Divergent with an eye on the idea that beating someone else up feels really good, even getting beaten on and standing back up can feel good, but is it actually good? Is this an appropriate use of force? Divergent won’t ask that question, so you’ll have to ask it.)
Our heroine is drawn deeper and deeper into this dark mess, drawn away from her family and their stabilizing influence. Something bad happens, the fun and games go too far, she goes too far, and she’s left having to reconcile the two together. Maybe she goes back to her aunt, maybe her aunt hands her off to a burned out cop to sort her out and learn real world application. I don’t know, it could go a lot of different ways.
Some Real Talk:
Some of you may be going: did you just use street fighting as a drug metaphor? I did because that’s exactly what it is. “Street fighters” (the “safe” ones anyway) are getting high on adrenaline. It’s not a high the same way cocaine is, but it is addicting though the addiction is more psychological and emotional than physical. When we look at “conventional” street fighting (as opposed to the upper echelons of criminal street fighting) that’s essentially what it is. The training sequences in Divergent aren’t really Tris becoming a crazy badass, but they are actually a pretty good reference to what actual street fighter “training” looks like and even feels like. Stupid kids bouncing off the walls and playing with dangerous toys. It’s dangerous, stupid, wasteful, and they’re not actually learning anything. They’re just daredevils looking for their next adrenaline rush. Druggies getting high. Feeling good versus being good. Feeling powerful versus being powerful. And that’s the thing. Tris feels good, she feels powerful but as much as the novel would like me to believe she is, she’s really not (in hand to hand) because she never spent any time actually learning. Surprisingly, you don’t actually learn much from getting beat up or beating up other people.
This doesn’t mean street fighters aren’t dangerous, they are because of the confidence, the aggression, and the willingness to use what they know. This is especially true when a street fighter is paired with a gun or a knife because the necessary skill level to use the weapon effectively decreases and their ability to do mortal harm (even accidentally) significantly increases. If there’s one thing a street fighter knows how to do, it’s how to take the initiative, and if they can get in first and fast, the fight will go in their favor. This will put them ahead of most conventional martial artists, especially if those martial artists have never prepared themselves or gotten training for dealing with the street.
Conventional martial artists require a few changes in perspective before they can really start using what they know as a form of self-defense. However, if they survive to get that change in perspective then they have the potential to become much, much more dangerous than the average street fighter.
Of course, I’m working off the assumption that your street fighters are stupid teenagers. If they’re criminally savvy gang members, cartel, or other criminal elements (even retired) who can go toe to toe with cops then it’s a whole different ballgame. I advise against it (not just because the price for joining criminal organizations can be exceptionally high for women and they tend to skew pretty misogynist anyway) mostly because that sort of training isn’t free. If a criminal is teaching your character something, it’s because they’re making an investment and that investment is going to pay off… one way or another. However, what they’re teaching your character to do will align better with their own history of martial training. At this point, we’ve moved beyond conventional “street fighting” and into quasi-military type training.
Teenagers and Fight Clubs, on the other hand, will give what they know away for free (provided you can survive the initiation) and while walking away isn’t easy, it’s ultimately less messy. (Your friends and family are all dead kind of messy.)
The Chauvinism and Misogyny Tango:
The other side of the street fighting/martial arts dichotomy is this: the chauvinism and misogyny tango. Because of the way it draws on more, erm, primal urges, street fighting tends to have a clear break down in the perceptions between boys and girls. Boys fight boys and girls fight girls. All things are not equal and, like with some gangs, girls may end up being “property” or “trophies”. “Girls can kick butt too!” will end with other girls because the general cultural assumption that girls can’t take on boys will be in play. Even if your MC can take on the boys, she’ll still be relegated to her status as “girl”.
This is why I recommend looking at Fight Club because the misogyny you get out of the book is a pretty typical.
For a character who grew up in a situation where women fighting isn’t even a question and are obviously equal to men, this is going to come as a bit of a shock. If not as a hard, sharp slap across the face.
Knife Fighting and Judo aren’t about stature or strength, it’s all about control:
Trained knife combat is all about surgical precision, speed, and careful control. Untrained knife fighting is all about flailing wildly at your opponent and stabbing first. It’s a knife, your chances are usually good you’ll hit something vital, especially if you aim for the torso. I really recommend going through Michael Janich’s Martial Blade Concept videos on Youtube. Really. They’re snippets of his larger program but it’s all about basic knife fighting and practical advice about what you’re likely to encounter on the street. This is self-defense with a knife and it’s meant more for police than for the average untrained person, but his videos are a good resource. “Street fighting” knife combat isn’t going to look like this though. Knife fighting isn’t really fancy. Unless, I guess, your character uses a balisong.
Judo isn’t about physical strength and neither is jiu-jutsu nor aikido. If you try to base your throws around upper body strength alone, you will hurt yourself. Thousands of students make this mistake every year, the long line of strained backs and spinal injuries are all the evidence we really need. Judo is all about balance, mobility and stability, proper application of force, evasion, etc. It relies on body mechanics, an understanding of rotational forces, and destabilizing an opponent’s base. It’s not about size. Smaller individuals actually have an advantage in judo because they are closer to the ground and, regardless of size, women with their lower center of gravity (bequeathed by skeletal structure and fat distribution) are actually well-suited to this martial style. On the other hand, large opponents tend to be overly reliant on their size and strength.
Pick up Wally Jay’s Small-Circle Jujitsu as his work has had a lasting effect on the modern American self-defense.
If your character is interested in not killing people, they are more likely to keep the knife sheathed and transition to it if they have to. Most of the basic hand to hand techniques they know may require two hands anyway and if they get jumped they’re not going to have time to pull their knife anyway.