Swordsman & Geek

A Midsummer Night’s Blog

You are reading the archive for the category: Geek Stuff

The Death Star meets Propio, Apropiado, and Transferido

In the last article I described the Spanish True School’s Timing Contexts.  (Link)

Here is the table again for reference:

Times and Timings in Spanish True School

Time Offending Timing Simple English Executive\Dispositive Fencing Context
Before (not in time) Propio Get First Intention Action
During (in time) Apropiado Give (Given) Dispositive Attacks into preparation,
Multi-Intention Attacks
After (possibly in time) Transferido Steal (Stolen) Executive Parry-Riposte,

We can easily see these concepts in action by considering the actions of the first two Death Stars.

Propio – The Death Star Attacks Alderaan

Alderaan is at rest and the Death Star strikes in the before time, totally blowing it away with a Propio Medio Proporcionado.  It’s evil, but it worked.

Apropiado – The Rebel Fleet Attacks the Death Star at The Battle of Yavin

The Death Star is moving into position to attack and is destroyed while preparing to fire with an Apropiado Medio Proporcionado.  You can’t “fire when ready” when you’re dead.

Transferido – During the Attack on the Second Death Star the Death Star Attacks the Rebel Fleet

The attack is underway and the Death Star counterattacks with a Transferido Medio Proporcionado!  It’s a Trap!!!

Bonus Transferido – During the Death Star’s counterattack, the Rebels counterattack the counterattack

The Rebels have reversed the Emperor’s Transferido with a Transferido of their own.   Yeeee-hawwww!


Challenging the status quo without losing yourself

I have been in the situation where I felt I needed to challenge the conventional wisdom about a sword tradition and there are good ways and bad ways to tackle that problem.

Full title: Saint George and the Dragon Artist: Gustave Moreau Date made: 1889-90 Source: http://www.nationalgalleryimages.co.uk/ Contact: picture.library@nationalgallery.co.uk Copyright © The National Gallery, London

Beware when fighting monsters that you don’t become one yourself.


In my opinion, it is most effective to concentrate on the **work** instead of the **person** in the counterargument. If you have a position there’s a decent chance we want to hear it, hell, we need to hear it if the position has merit.

However, not all positions are good and we have seen plenty of half-baked nonsense in our time. Polish up your argument into its best form, have a friend read it for tone and clarity, and set it out there without assigning intention or motivations to the other researcher or the original author (unless the source definitively tells you, “By this I mean X, Y, Z…”)

Good work can be made better by critical process. I’ve been wrong and errors in my work have been fixed by others. (“There is no such thing as a transversal step backwards.”  Oops.  Fixed it.)  It is not wonderful to be wrong, but I would rather see my stuff fixed than propagate errors.

As an aside, translation is an art. The lovely Dr. Curtis did a presentation on a single passage from Don Quixote and how the translation style changed the outcome of each piece. That’s expected.  Multiple translations in different styles is a feature.  I think we all want access to the different insights, tone, and flavor that each translator brings to the text.  If you want to disagree with a translation it is probably about choices made.  You could say, “By making this choice, the emphasis on these keys aspects is missing.  Or, “This choice loses this context which I think is essential.”  That’s constructive and potentially useful to the neutral observer.


Take care of yourself first. When you form a critical position, how you do that will make a lasting impression on the people reading your argument. When you use ad hominem attacks, assign nefarious intention, or imply fraud you have gone beyond academic discourse into personal grudges. At that point you’re going to see friends and allies rally to defend the character of the original researcher.  Once that starts it can be very difficult, even if you are absolutely correct, to have a productive discussion.

There are ways to challenge existing work without compromising your personal reputation. Sometimes it’s absolutely necessary to do this to foster growth in the community and to correct misconceptions. Maybe that necessary conflict is being driven by you and your work. I’ll be the first to admit that doing this well isn’t easy but if you can thread that needle you’re going to be an asset the community will continue to draw upon going forward.

Consider having a friend read your argument to pull out things with loaded words like “refused”, “obviously”, “clearly”, “ignores”, “deluded”, “recklessly”, and so on.  What I want as a reader is the core of your argument presented in its best form.  I can make decisions about the personal motivations on my own.

For example,

  • I think there is real value in considering this alternative which I think better reflects X,Y,Z…
  • By considering how the images were chosen we can gain insight into X,Y,Z…
  • I think this is an error based on this <citation>.  Based on that consider this alternative which allows us to…

Each of those methods helps the reader understand there is potential value in at least considering your position.  By buttressing the argument with citations  and avoiding loaded language you open up some space in the dialogue and you preserve and protect yourself by avoiding self-inflicted wounds.


Don’t be an authority and instead be a resource. I’ve seen multiple examples of individuals trying to be an authority (Maestro-cop to the universe) and their work collapses underneath them as their attempt to assert authority is outpaced by the increased knowledge of the growing community.  Having had the benefit of watching these implosions I made a commitment to myself not to walk down the same road.

By refusing to own the tradition but rather trying to build and restore it, I permit myself the necessary space to be wrong and correct the work as I gather new evidence.


If you have done enough research to disagree with an established interpretation, you have value whether you are right or wrong.  By encouraging you to argue well, I hope to preserve your place in the community for my own selfish reasons.  Critical feedback and challenging of existing work is essential to what we do. I hope you’ve got something useful and can present your work effectively.

Building a Flail Trainer

This is how we built a two-handed 3-headed flail trainer with parts you can find at your local hardware and sports store.   The method described here isn’t the only way to build a flail and the training weapon here is experimental.  If you build it there is every chance you could injure yourself with it if you get as crazy as my brother might.  So… I warned you.

The parts list:

  • 6-foot closet pole (1.8 meters)
  • 2 matching screw-mounted rope hooks
  • 2 bolts with matching nuts
  • Nylon paracord
  • Duct tape (of course)
  • 3 racket balls
Flail parts laid out

Flail parts laid out

The Measurements

Our flail has a 3-foot handle and three approximately 3-foot “chains” including the heads.


1. Cut the closet pole down to size.  (For our first flail we tried a length of 3 feet (0.9 meters).  It worked fine but we’re thinking of making the next handle slightly shorter by about 4 inches for a total haft length of 32 inches (0.8 meters).)

2. Use the rope hook as a guide for marking your drill target.  We chose to bring the hook as far down into the pole as possible to increase the strength of the trainer.

Use the Rope Hook as your Stencil for your Drill Guide

Use the Rope Hook as your Stencil for your Drill Guide

Marked and Ready for Drilling

Marked and Ready for Drilling

3. Slowly drill all the way through the pole and remove any frayed edges.

4. Align the two Rope Hooks facing each other to form the “chain’s” looping anchor point on the flail.  At this point you may want to remove some stock from the pole to ensure a snug fit by marking the end of the shaft and using a round file to remove the extra.

Marking the Head of the Flail to Remove Extra Stock

Marking the Head of the Flail to Remove Extra Stock

We will file that out

We will file that out

Filing out the Extra

Filing out the Extra. (It’s easier if you use a vise.)


Stock Removed. Also, now it looks like the Bat symbol. (Batman would be proud to train with us.)

4. Now that you’ve created a perfect fit, fasten both Rope Hooks onto the shaft with the bolts so that they face each other to form a looping “chain” anchor point.

Two Rope Hooks makes a good loop.

Two Rope Hooks makes a good loop.

Fastened Down Tight

Fastened Down Tight.

5. At this point you have created something dangerous with the exposed metal bolts.  I recommend using a hacksaw to cut the exposed bolts off and then cover anything with sharp edges with a layer or two of tape.  You want to minimize the possibility of cutting yourself if you accidentally hit yourself in the head.

6. Next, drill a hole through each of three racket balls.


Yep… That’s a hole clean through a racket ball.

7. Run your nylon paracord through the hole.  To do this, we used fishing line.

Push a loop of fishing line through the holes and then insert your paracord into the loop on the far side. Pull it through and, "Tada!" it is threaded.

Push a loop of fishing line through the holes and then insert your paracord into the loop on the far side. Pull it through and, “Tada!” it is threaded.



8. Tie the cord just underneath the flail head using a bowline knot.  ( Click here to see how to tie this knot! )


Tie it with a bowline knot.

9. Tie it to the anchor point using the same bowline knot.  (Repeat the process for all three flail heads.)

10. We used duct tape on the edges of the Rope Hook to avoid any grab on the nylon rope “chains”.


It doesn’t have to be beautiful.


The Completed Flail Trainer

Yep... It is a flail.

Congratulations… you have given birth to a baby flail with a 3-foot shaft and 3-foot chains.

This is much lighter than an actual flail when you swing it around but you still get a scary amount of force with it such that hitting people is probably a terrible idea.  While exercising the flail we found that swinging it at high speed didn’t seem to cause any problems with the racket balls but striking solid targets caused cracks around the drilled holes which would be eventual failure points.

Still, not bad for flail 1.0.


Rover Construction


I’m building a rover as a test platform for our Wi-Fi embedded controller.

Pucks Rover

Puck's Rover which might soon conquer the earth.

Here is the assembled chassis with four-wheel-drive installed for the little guy.  You can see each tire has an independent motor with control lines in red and yellow. With each tire operating independently, we should have a much greater range of mobility including stationary turns and spins.

The little circuit board I am holding up is our 16-bit Rabbit computer with integrated Wi-Fi.  I will probably use it to serve a web page with controls for the device.  (Here is a link to the RCM5600W.)

My next work project is putting together a blog on this project so at some point in the near future I will post a link to it.  The blog will be written informally with an engineering focus but hopefully in plain enough language that a non-engineer can follow it.

As a professional computer engineer, I cannot confirm or deny that this project is the creation of a robot overlord. He may or may not be designed to dominate humankind in an empire ruled by sentient machines drinking large amounts of coffee.

Spanish Fencing Notation Part 5 – Strength of the Weapon






Degrees of Strength in the Weapon

The amount of physical power you can exert with a sword varies along the length of the blade.   The part of the blade closest to your sword-hand has the most mechanical advantage and the further you move away from your hand the weaker you become.  The Italian system typically breaks the sword down into three parts; Strong, Middle, and Weak. The same will occur for any object held in the hands whether it is a longsword, rapier, or even a stick.

Leverage with Different Objects

Leverage with Different Objects

While the Spanish understand this and often refer to the Strong and Weak as well, Carranza labels these parts as the Near, the Middle, and the Remote.

Carranza’s Philosophy… f.167 (1569, pub.1582)

“Know that in the angle of the straight line, the sword has three parts. I mean that its numeration starts from the tip (as we will discuss later), and the strength increases as the numbers are multiplied until stopping in one of the centers. All this graduated quantity is divided in three equal sections with respect to the length, but they are unequal with respect to each one’s quality. You should be aware that the part next to the center’s strength is called near in this Art; the second portion, because it is between the strong and the weak and between the increase and the decrease, is the middle; and the last part is called remote.”

~Translated by Mary Curtis

Another method of describing the transition between weaker and stronger leverage is by numbering the sword into degrees of strength.  This provides us with more information when describing engagements.

Image from Carranza’s Philosophy… f. 178 (1569, pub. 1582)

Carranzas Degrees of Strength

Carranza's Degrees of Strength (Click for High Resolution)

Notice that the blade is numbered from one, the weakest portion, to gradually higher numbers that indicate more strength.  The effect of the notation is that higher numbers defeat lower numbers which is intuitive and easy to follow.  These graduations of strength in the blade can provide an instructor with a greater degree of specificity when speaking with the student.

“Engage his 4 with your 6.”

“Shift the engagement from your 3 to your 8.”

Sword with degrees marked in tape

Alonya's sword with the degrees of strength marked in tape for training

Carranza’s Leverage Demonstration

Carranza proves the mechanical advantage by applying a finger to the weakest part of a sword to demonstrate the combined effect of two different types of leverage working simultaneously.

First and Second Class Levers

Carranza’s Philosophy… f. 179 (1569, pub. 1582)

“Then place the first finger of the four (called the index) on the tip of the sword at the beginning of the violent movement, and hold it firm, so that it makes two right angles with the sword. And I tell you all on behalf of the truth that even if many strong arms join together to move it from the place where the finger is, not removing it to the sides nor below, they will not move it. They will not be able to move it upward either nor make a violent movement with it upward in any way, as you all will see in this illustration that serves for the violent and natural movement.”

~Translated by Mary Curtis

DANGER: A Bit of Physics…

To understand Carranza’s illustration, we must first define torque.  When physicists talk about the linear motion of an object, we can talk about forces acting on the object.  For example, if I want to move a sword in a line, I can apply a force to the sword for a thrust.  These forces might be gravity pulling the object toward the earth, a fencer lifting a weapon from a table, or a lunge pushing the weapon forward.

Just as a linear force moves objects in a line, torque rotates objects around a fixed point.  When we wish to rotate an object we apply force to the object to achieve torque.  The length of the object (or moment arm) affects how much torque we can achieve with a given force.  The further from the point of rotation you can apply your force, the greater the torque applied.  Just as you can use a longer wrench to unfasten a sticky lug nut, you can also achieve greater torque by engaging the adversary’s weapon further from the axis of rotation.  In plain terms, pressure on the adversary’s weapon in the weak of the blade provides you with much more strength than engagement closer to his hand.

The Most Common Discussed Sword Lever

The weapon will act as a Second Class Lever when the entire arm is considered.

The Sword as a Second Class Lever

The Sword As a Second Class Lever Hinged at the Shoulder Joint. (The swordarm shown here is a reversed and edited image from Carranza's text.)

The axis of rotation might be the shoulder joint as shown here, or the elbow or wrist instead.  Pushing at a 90 degree angle to the sword provides us the greatest amount of torque.

Without getting too deeply into mathematics, you can see that when you double the length of the lever, you also double the torque you can achieve with the same force.

  • Torque = (1 foot) x (10 pounds) = 10 foot-pounds of torque
  • Torque = (2 foot) x (10 pounds) = 20 foot-pounds of torque!!
  • (Assuming that both are applied 90 degrees to the moment arm.)

This tells us that if we apply force further away from the shoulder in the weak of the blade we achieve greater torque than the same force applied to the strong.

You can demonstrate this in your own class by having your largest fencer grip a sword in one hand with an extended arm.  Have the smaller fencer apply downward pressure to the tip with a single finger while the stronger one tries to lift the weapon from the shoulder.  The large fencer will feel the torque in the shoulder because the entire extended arm and weapon becomes a Second Class Lever.  If the large fencer tries to lift from the elbow or wrist, the torque will also be exerted there as well with pressure on every joint resisting the downward motion.

The Hidden Lever

There is another type of lever acting here as well that we can see by looking at Carranza’s image.  In this image a heavy weight is suspended from the hilt and with a single finger we can lift it across an invisible fulcrum.  What is the missing fulcrum?

Image from Carranza’s Philosophy… f. 179 (1569, pub. 1582)

Carranzas Demonstration of Leverage

Carranza's Illustration of Leverage Lifting a Heavy Weight (Click for High Resolution)

Carranza’s image provides us with an example of the sword as a First Class Lever.  The finger on the blade’s weak lifts the heavy weight tied to the pommel with the unseen fulcrum being the hand of the fencer holding the weapon.

Sword as First Class Lever

The Sword as a First Class Lever held by this left-handed swordsman.

The conflict between the fencer’s gripping force and pressure applied to the weapon is one of the mechanisms you might use to disarm an adversary.  For example, in the previous article Carranza indicated that fingernails up is the weakest position of the hand.  By applying downward pressure or a strong beat to the adversary’s weapon, you might be able to disarm your opponent.  Salvator Fabris shows two possible disarms against an adversary in fourth (fingernails up) in plate 181.

You can demonstrate this in your own class by having your largest fencer grip a sword in one hand fingernails up.  Have the smaller fencer apply downward pressure to the tip with a single finger.  The strong fencer will feel an intense amount of pressure at the fulcrum point, and the smaller fencer will probably be able to push the tip downward.  If this pressure is applied quickly and with force, it could result in a disarmament.

When Opposition Occurs Natural Defeats Violent

In a natural movement, the blade falls while in a violent movement it rises.  According to the Spanish when two blades are in contact with equal degrees of strength, the fencer pushing downwards has the advantage over the fencer attempting to lift his weapon.  The fencer pushing downwards can bring the weight of his upper body to bear into the engagement while the fencer resisting from below must rely solely on the muscles in the arm.

Pacheco argues that the Natural movement “…cannot be defeated by another, due to its noble nature,…” and Ettenhard echoes this.

Ettenhard in Compendium of the Foundations… p.89 (1675):

“…and it is very clearly shown that he [don Luis Pacheco de Narvaez] said it because of the natural movement, since to it alone belongs the subjection, and in conclusion, it alone is superior to all, due to being the noblest, quickest and strongest.”

~Translated by Mary Curtis

Changing the Relationship of the Opposition

When two blades come into opposition changing the point of contact can increase or decrease your strength in the engagement.  Within the Spanish system this would be increasing or decreasing the degree of the sword.

In German longsword the practice of lifting the weapon to change a weak engagement to a stronger one is called ‘Winding’.  The Spanish have a similar concept called a Movement of Increase.  If both fencers start with equal engagement, Ettenhard tells us that by lifting the weapon and carrying it into the line of offense we can strengthen our engagement.

Ettenhard’s Compendium… p.119 (1675)

“…the movement of increase, which is made in order to graduate the sword. Since for this reason more strength is acquired and increased, it is appropriately given this name but not because it is of a different type from the ones mentioned in the principles that have been defined, since this action falls (with more certainty than to any other) to the mixed movement aligning lateral and violent.”

~Translated by Mary Curtis

In contrast, moving from a strong engagement to a weaker one is called a Movement of Decrease.  If both fencers start with equal engagement, then by lowering the weapon and moving away from the line of offense we weaken our engagement.

Ettenhard’s Compendium… p.119 (1675)

“The movement of decrease is the one that is made in order to reduce the strength, disgraduating the sword, whose action belongs legitimately to the mixed movement of offline lateral and natural…”

~Translated by Mary Curtis

This again reinforces that the high line provides the greatest advantage and that engagement from below is considered weaker by the Spanish tradition.

A Riddle of Inertia, Momentum, and Energy

It might be best to consider a fencer’s riddle and then examine some physics to provide us with an answer.

Riddle: How can you parry a greatsword with a dagger?

DANGER: A Bit More Physics…

Inertia is an object’s resistance to a change in the state of its motion.  Any object that is not moving requires force to accelerate it. For example, to swing a cut you will apply a force to the weapon to accelerate it towards the adversary’s head.  If we ignore rotational motion in this discussion, the required force is defined as:

Force = (mass of sword) x (acceleration)

In order to decelerate or stop a moving object you have to apply the same type of force.

Momentum is defined as the product of velocity and mass which does not provide us much perspective into its effect in swordplay, but it is useful for determining behavior during collisions because momentum is conserved.  That means that a heavy object moving very quickly (like a greatsword) that is forcibly stopped by a smaller one will transfer momentum to the smaller object.

Momentum = (mass of sword) x (sword velocity)

Kinetic Energy tells us how much energy is delivered with an attack.  The most important element in delivering a powerful attack is the velocity as shown here:

Kinetic Energy = 1/2 x (mass of sword) x (sword velocity) x (sword velocity)

By plugging in some numbers we can see how this might turn out.  First, we can weight the two equally as shown here:

  • Mass = 2
  • Velocity = 2

Kinetic Energy = 1/2 x (2) x (2) x (2) = 4

If we double the mass we achieve an increase in energy as shown here:

  • Mass = 4
  • Velocity = 2

Kinetic Energy = 1/2 x (4) x (2) x (2) =8

If we instead double the velocity we achieve a much more powerful attack:

  • Mass = 2
  • Velocity = 4

Kinetic Energy = 1/2 x (2) x (4) x (4) =16

Carranza Answers the Riddle

In Carranza’s Philosophy on folio 180 we see an odd figure with a dagger, a sword, a hand, and a head surrounded by geometric figures.  (This is one of only six figures in the treatise.)

Carranzas Analogy for Momentum and Inertia

Carranza's Analogy for Momentum, Inertia, and Energy (Click for High Resolution)

If you close one eye and lift your index finger, holding it away from your face like the man in the image, it obscures only a very tiny portion of your sight.  As you bring your finger back towards your eye (the source of your sight) it becomes larger and obscures more.  If your finger is close enough to the origin, it can block out your entire view. What this tells us is that even a tiny finger can obscure a large object when it intercepts the vision at the beginning.

Carranza uses this as an analogy to tell us that in the same way, even a dagger can parry a powerful greatsword if it intercepts the cut close to the beginning of the attack. (Looking at the image above you can imagine intercepting the attack where it begins at the point labeled N.)  Because the velocity is close to zero it is easy to halt (Inertia), the Momentum is low, and the Kinetic Energy delivered at the beginning of the cut is also very low.

If you intercept the same cut at the point labeled O, the velocity of the attack has increased and your parry can easily fail.

Riddle: How can you parry a greatsword with a dagger?

Carranza’s Philosophy… f.180 (1675)

“These movements are weak in all their beginnings,… “

~Translated by Mary Curtis

Answer: Parry the attack when the velocity is zero or very low.


I have used the physics described by Isaac Newton’s Philosophiæ Naturalis Principia Mathematica to explain some of the different aspects of how a sword functions but this text wasn’t published until 1687.  The equation for kinetic energy was not discovered until 1829 by a French mathematician named Gustave Coriolis.  Even considering that the fencing masters of Spain used the physics and motion described by classical authors like Aristotle, they knew qualitatively how weapons moved in combat which provides their work with a high level of sophistication.