Double leg takedown from the Bauman Fechtbuch or Codex Wallerstein, Author unknown
They seem like good friends.

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Double leg takedown from the Bauman Fechtbuch or Codex Wallerstein, Author unknown
They seem like good friends.
From a lesson taught last night.
Sometimes, I can be incredibly slick when fighting.
Armoured and Un-Armoured Longsword
[22] This is the text and the gloss on yet another of the Wrath-hew:
Be Stronger against, Wind, Stab. If he sees, then take it down.
(Krakow/ “Goliath” version of Pseudo-Peter von Danzig’s Glossa, book from c.1510, text from before 1452)
[49] Yet one play
Mark when you stand in the high guard and he stabs low to you Then stab from above down between his sword and his forward hand and push the pommel to the ground and wind your point on his sword's blade through below his sword and attack him to his right side.
(illustration from Krakow/ “Goliath” version of Pseudo-Peter von Danzig’s Glossa, book from c.1510, text from before 1452 - actually text is from the 1452 Rome version of P-PvD, since Krakow is not transcribed on Wiktenauer for the armoured section)
Here we see two kinds of longsword fight. The immediate difference should be obvious. In the first, the fencers aren’t wearing armour. One isn’t wearing shoes, giving a great example to those of use who fence in toe shoes.
In the second, they’re in armour. Full harness, head to foot.
This necessitates a different kind of strategy. In the first image, the plan is simple - stab them in the face from as far away as possible. In the second, both fencers are holding their sword in the “half-sword”, “shortened sword” grip with the non-dominant hand on the blade.
This grip gives better control of the point and better leverage. You need these because in order to hurt an armoured opponent, you need to get the point into the gaps in his harness (inner thigh, armpits, inner elbow, visor etc.) and these are small targets.
The downside, obviously, is a lack of reach. However, without the point control and leverage of the half-sword grip, it’s unlikely that a regular gripped thrust could find the harness’s openings.
"If you want to be happy in your fighting, be lively, do not maintain the plays for long. In addition, laugh in a pretty way! And be serious [about serious things]. Trust in the sword, Which Talhoffer teaches."
Excerpt from the Opening of Hans Talhoffer's Personal Manuscript (1459)
A dirty trick in Michael Hundt's 1611 treatise "A New Illustrated Fencing Manual on Rapier"
If your grace wants to do a dirty trick, it is in fencing or in brawling, in dagger and rappier alike, then use nothing more than these words, "I won't fight with the two of you, rather only with one" and when he wants to look around, he comes up short, and you can thrust him through and through.
Han's Talhoffer's Württemberg Treatise (1467)
are there any historical fighting styles/techniques that were particularly anti-armour, without relying on particular anti-armour weapon tools like the spikes on hammers? (emphasis on without relying on, not necessarily excluding)
You're kind of asking two questions there, because the question is "did styles doing <x> exist, that focused on not using tools for <x>?"
The answer is a big "No". With extra context.
The problem is, within European (and a lot of other global martial arts, I've noticed) combat, fighting/fencing is broken into two distinctive categories:
1 - Unarmoured. This covers longsword, rapier, katana, jian, saber, whatever. Almost every weapon out there is used in a "default" state for this context. Your opponent is wearing little to no armour, and you are not specifically having to handle that obstacle.
2 - Armoured. This is it's own beast, with it's own advantages and restrictions. Your range of motion is semi-restricted, vision, etc. You are also much more durable, with narrowed target areas. Fighting now needs to focus on attacking those areas, save in the case of special weapons like polaxes and pikes or lances from horseback.
Both categories, while they have some overlap in the ways they are trained and fought, are very different beasts.
However, half-swording generally arises as a way to deal with armour, using a weapon that is not ideally suited to anti-armour, so exists in a context that approaches that which you are asking about.
Additionally, daggers (particularly the narrower types used in the late middle ages) tend toward this function, being designed to puncture through gaps in armour, yet are generally use in a civilian context, and to finish armoured opponents when rendered helpless.
What is Bloßfechten
Within the German school of fencing, Bloßfechten or "bare fighting" is the technique of (armed) fighting without significant protective armour such as plate, mail or a brigandine. Vulnerable targets like the head and upper torso are totally unprotected except for normal clothing during Bloßfechten. The lack of significant torso and limb protection leads to the use of a large amount of cutting and slicing techniques in addition to thrusts. These techniques could be nearly instantly fatal or incapacitating, as a thrust to the skull, heart, or major blood vessel would cause massive trauma. Similarly, strong strikes could cut through skin and bone, effectively amputating limbs. The hands and forearms are a frequent target of some cuts and slices in a defensive or offensive maneuver, serving both to disable an opponent and align the swordsman and his weapon for the next attack. (description via wiktenauer)
The other form of armed historical combat is Harnischfechten, or "armoured fighting", which is fighting in protective gear, most specifically plate armour. The techniques used are rather different, as the need to circumvent the protective armour completely changes the way in which the longsword is used.
Now this is something that by now any HEMA practitioner should be familiar with, or at least those who are learning German martial arts (Kunst des Fechtens), but just to reiterate: If you fence with longsword, and you are using techniques that assume that your opponent is not armoured, and likewise you are defending yourself as if you are also not wearing any armour, what you are practicing is bloßfechten.
This is Bloßfechten:
And so is this:
So what makes these bloßfechten is the fact that they are attacking and defending themselves with longswords as if they are not wearing plate armour. Only wearing t-shirts and light gloves, like in the top drill, can be referred to as minimal gear fencing, but wearing additional safety gear for added protection against more committed attacks does not change the nature of the techniques.
In other words, wearing your full competition-grade SPES gear, sparring gloves and joint protection does not transform the type of the fencing you are doing, it’s still unarmoured fencing!
For comparison, this is Harnischfechten:
But so is this:
So though these last two chaps are wearing gear that is not very far off to what you might find in some unarmoured longsword competitions, what is key to understand is that they are using Harnischfechten techniques (or Fechten in Harnisch zu Fuss, literally "fighting in armour on foot"), specifically designed to overcome the problem of fighting men clad in full plate armour. Please note that this is quite different from the random armour bashing we see in modern armoured combat games (HMB, ACL etc).
Which brings me to the last point. Bloßfechten is a type of armed combat, and some argue that to practice it properly you should attempt to recreate the conditions in the Fechtschule (a 16th century competition based on the unarmoured duel with safety rules barring the more lethal and damaging sort of moves within the limitations of available equipment and commonly agreed concepts of acceptable risk at the time), but to claim that bloßfechten and modern “competitive longsword/sport HEMA” are two different things is also a misconception.
So this is Bloßfechten:
But then again, so is this:
The gif is just a small training exercise, and the video is an actual competitive tournament (Fechtschule Brugge), but the fact that one is an actual competition (the dreaded ‘sport’ word!) and the other one isn’t doesn’t change the fact that they are both f@$%&*! bloßfechten!
So the next time someone tells you they don’t compete nor fence for points, or that they don’t believe in wearing safety gear, or that they only wear period shoes etc because they “do proper bloßfechten”, be safe in the knowledge that they are probably quite full of it.
We are ALL doing bloßfechten mate