The following is a guest contribution to the blog by my long term gurbhai (brother in our martial school) Asante elucidating in great technical detail the immense science (vidiya) of the weapons (shastar) we use in SV.
When I first found Shastar Vidiya, what really shined for me was the system’s attention to detail. In strategy, body mechanics, fight mentality and even attention to underfoot conditions and how they affect fighting ability. But nowhere is this attention to detail more obvious than in the design of the various weapons. One of my most memorable moments when first attending a Shastar Vidiya seminar was getting to hold a variety of Indian weapons and feeling how much of a difference there was between the extremely well balanced antique swords, and some of the poorly balanced modern ones.
Coming from an engineering background, I found the difference in design fascinating. Even some of the more cumbersome looking wide and heavily curved weapons felt astonishingly light in my hand and were surprisingly easy to wield. This led me to create this quick guide to what makes a “good” sword in SV and highlighting why we aim for those qualities.
Control
When choosing a sword, generally speaking we want it to be as easy to control as possible, as well as easy to cut with. Meaning a sword which comfortably generates power, but requires minimal effort to move, bring to a stop or change its direction.
Just like in cars this largely comes down to stability and engine response. In cars, engineers focus on maintaining pressure on each wheel and contact with the ground by tweaking the suspension and using an electronic system to control power.
We focus on how contact is made with the hand, how much strain is on the wrist and how natural stabilising forces, along with rotational inertia, are combined to achieve better control and power generation. To understand how this works we first have to first understand tipping point design and stabilization.
Stabilisation
An object will naturally stabilise itself and return to equilibrium if its center of mass does not move beyond a tipping point. This is known as static stability, and though it does not entirely determine how an object behaves dynamically, it does give us a very good indication. Natural stabilization can be a good or bad thing depending on the application.
In shipbuilding for example, you want a very low center of mass and a large separation between tipping points to prevent the ship from capsizing. When designing an electrical switch however, you want to minimise stabilization by having a single tipping point which reduces the energy required to flip the switch, which ensures switches actuate very quickly, thus preventing arc damage.
With swords, we want a combination of both, tipping points which reduce the energy required to move or hold the blade in certain ways, but enough stabilisation to reduce strain on the wrist when wielding it.
When looking at the tipping points of swords, we consider how the center of mass effects leverage, how tipping points relate to our desired range of motion at the wrist, and how stabilization can help us to find and maintain wrist posture.
To use the car analogy, we’re looking at how stiff or soft we want the suspension to be. In a car the suspension is used to not only absorb shock, but to return the car back to equilibrium where all wheels are maintaining pressure on the ground. Too hard or too soft and you risk some wheels leaving the ground or others taking all the pressure, thus causing damage and loss of control. A similar thing happens with the wrist. Muscles work in pairs much like wheels on a car and have optimal length-tension relationships which are determined by the angle of the joint. The further you move from this "ideal angle" the less force you can generate and the more strain you put on the tendon/muscles.
If we had a hypothetical sword with a very low center of mass quite near the hilt, although our leverage would increase, the sword would be more reluctant to rotate and have less angular momentum (which I’ll talk about more later). This would reduce its power for cutting and increase the separation between tipping points beyond our wrist’s normal range of motion when wielding.
Though the almost horizontal tipping point and reluctance to fall forwards would be ideal for a thrusting grip/style, this is the opposite of what we’re aiming for when draw cutting. Draw cuts start somewhat like a punch with the sword fairly upright (perpendicular to the forearm), before falling through the target. A sword like this would increase the effort required to generate power and maintain our desired wrist posture.
Conversely, if we have a sword with a center of mass that is too high, although the sword would feel almost eager to fall forwards and generate a lot of angular momentum/power for cutting, our leverage will also decrease massively, thus increasing strain on the wrist. As for the tipping points, although they would be within our wrists normal range of motion when wielding, the separation between them would be too small to be useful. Just a little rotation would push the sword past its tipping point and prevent us from using its self-stabilisation to assist in controlling the sword.
Fit and Balance
Before assessing the static stability of a sword, we first assess the fit of the hilt. The plate on the bottom of the hilt should create a snug fit to the hand so the little finger and heel of the palm are in contact with the plate. This secures the hilt in place, reducing the requirement for grip and provides great purchase for heavy draw cutting. The contours of the hilt itself closely match the varying heights of the interphalangeal joints, and with the elliptical cross-section, help to make maintaining edge alignment intuitive and ergonomic.
The plate also provides multiple points of contact and leverage, which help reduce play and pressure felt in the hand. These points become primary when wielding in closer to horizontal positions and applying lateral rotations. Rather than just using the shaft of the hilt, we also press and pull on the plate with the bottom edge of the palm as an additional point of control for more precise manipulation. Finally, the plate helps to prevent bad habits like overextending the wrist and enforce good ones like using the entire arm/body to cut, by physically preventing over extension (forward rotation).
The second thing we check when assessing an Indo-Persian sword is its central equilibrium point. We want the sword to be balanced in such a way that it's slightly tilting forward. Meaning the sword will naturally move to a more ”ready” position for draw cutting. This angle also closely matches the angle of a relaxed wrist, making maintaining this position less strenuous. Some swords will have what is known as a “gun hilt” where the base of the hilt is shifted forwards so the little finger sits just in front of the center of mass, allowing it to act like a trigger for forward rotation, as well as a backstop for backward rotation.
The rear tipping point should align with the center of mass in such a way the sword is oriented as close to upright as possible. This makes the sword slightly resistant to backward rotation, meaning it will be easier to control when retracting a strike/movement, and faster off the mark from an upright position, which is granted by the unstable equilibrium. This may seem a little bit counter-intuitive at first, as you may think “don’t you ever draw back for a big cut ?” Well yes, but keep in mind the wrist has limited flexion (backwards rotation) and the closer you get to these limits the more strenuous it will feel. Also this tests only tell us about static stability, dynamically we have to counter inertia and torque as well as gravity. If the swords rear tipping point is too far back, it can feel almost like the sword has a lot of "drag" in drawn back positions due to excessive rotation in the hand.
The front tipping point should bring the wrist to its ideal tilt (between 15 and 30 deg) where the wrist is at its strongest for draw cutting, whilst the center of mass should align vertically with the tip of the sword. This reduces the effort required to find and maintain good wrist posture as well as the effort required to retract/raise the sword, without negatively affecting momentum for cutting.
Should the sword reach its tipping point after the wrist is at "ideal tilt", the sword will feel reluctant to hold the position, and slower off the mark when attempting to cut due to the stabilising forces. Tip alignment is important for thrusting (which are primarily upwards and hooking movements in SV) as we want to align the sword's center of mass with its tip for efficiency and have the blade to feel as stable as possible throughout the thrust. If the tip does not align with the center of mass in a strong wrist position, thrusting would require us to either adjust the tilt of our wrist to a non favourable angle, or thrust inefficiently, putting excessive strain on the wrist.
Rotational Inertia
Inertia and momentum are two sides of the same coin. An object's inertia tells us how much effort is required to get an object to move/change direction, whilst the momentum of an object, tells us how much effort it would take to stop it from moving. The more mass something has, the harder it is to move, and the more velocity (speed) something has, the harder it is to stop. The difference with angular momentum is that the velocity mentioned is rotational.
Momentum is Mass x Velocity, which can be written as Mass x Distance / Time. In other words Mass x the Distance you’re able to cover in a certain amount of Time. Well, the further you are from the center of a wheel, the more distance you cover in the time it takes the wheel to rotate, because the circumference is larger. This is why Olympic runners start at different points on a track, it ensures they all run the same distance.
Looking at the diagram and assuming both cars have the same mass, it should be clear that the green car travelled further in the same amount of time, thus had more momentum and required more energy to do so. Applying this to swords, the further the center of mass is from the hilt (the center of rotation) the harder it becomes to stop the sword from rotating, which can be great for power but negatively affects control due to the increased energy requirement for wielding.
Once the sword has moved beyond the tipping point, we rely largely on using the sword's mass and innate rotationality qualities to wield it and perform cuts. So after ensuring the sword feels well balanced in the hand, we check the changes in its angular momentum, inertia and velocity when performing a drop and bounce test.
These tests can be quite difficult to get a feel for, but what we’re looking for is smooth acceleration and or specific changes in momentum. The more specific changes refer to specialised weapons like Khandas, Kirachs and Kukris, which should fall in specific ways to aid the way in which they are used. But for typical Golias, Teghas and Sirohis, our priority is smoothness which is what we’ll focus on here. Smooth angular acceleration and changes in momentum help to keep pressure changes in the hand more predictable and consistent, making the sword easier to wield.
As I mentioned in the beginning, this is a lot like tuning performance cars where drivers want a very smooth engine response and power output. Imagine accelerating out of a corner at high speed when the engine suddenly jumps up in torque unpredictably. Not only would this throw you off, it would also make the car very difficult to control. Good engine response looks something like the picture below, smooth and flat.
To perform the bounce test, you gently bounce your sword against your forearm (wearing something protective) whilst moving through a full range of motion for a draw cut, but in reverse. So starting from the tip and making your way towards the hilt. The idea is to try to keep the bounce height as consistent as possible, whilst monitoring the feel in the hilt. Essentially what we’re testing is how the sword responds to manipulation when held at various angles. With a very* well balanced sword you should be able to make it all the way to the hilt without any drastic or unexpected changes in feel and bounce height. The distance between the tip of the sword and the point at which you feel a big change, determines the quality of the balance. The shorter that length is, the less well balanced the sword is.
Performing the bounce test requires a certain amount of sensitivity and experience to get the hang of, but I've created an approximation of the more simple drop test using physics simulation software.
The GIF below shows what is known as a double pendulum test which is highly sensitive to initial conditions and physical properties of an object. This allows us to study dynamic behavior in more detail. It has long been used by scientists studying sports like golf, cricket and tennis to analyse the efficiency of movement and the performance of sporting equipment. One study even goes as far as using this experiment in an attempt to design the “perfect” bat. But that’s far beyond my understanding and scope of this article. I’m using this test to simply show how the shape of a weapon can affect its angular acceleration and momentum when acted on by gravity. Which happen to be what we rely heavily on when wielding, so it’s a great fit for our usage.
On the left and at the top you have 2 setups with identical mass but different shapes. These are to be used as references which show how a shape alone can influence angular momentum/acceleration. On the right is a shape which resembles a typical Sirohi which we’ll be testing. The limbs on the test represent our arm and forearm, and the initial position is how we typically begin a real drop test.
Looking at the change in angular momentum over time for the Sirohi shape, and comparing it to the reference shapes. We can see that the taper and shape of the Sirohi have managed to keep the changes in momentum relatively flat and smooth. Assuming it has good stability, this would be a very comfortable sword to wield.
As for changes in angular velocity, although the straight shape generates the most angular momentum, it is slower off the mark than the circular and Sirohi shape. It also picks up speed quite suddenly after its initial movement. This could potentially make it more difficult to wield.
Naturally, this was all performed on 2D simulation software so it’s not 100% accurate, but it does give us a good indication of how shape affects angular acceleration.
In addition to the elements we've already spoken about, there are other features we look for in swords such as;
Counterbalance - This is affected by the weight of the blade in relation to the weight of the hilt. It speeds up instability corrections giving the blade a "flame like" quality, allowing it to dance in the hand as my teacher would say.
T section spine - This makes the blade lighter overall without loosing too much rigidity.
Diamond section tip - This improves thrusting ability especially against armour.
Double edged "beak" - A double edged top portion of the sword, making what we call "plucking" strikes (essentially a reverse cut/thrusts) more efficient.
As well as the more obvious stuff like steel quality and edge geometry.
It's important to note that none of these qualities will automatically make you a better swordsman, or able to perform the famed deep draw cuts that tulwars were known for. In the same way driving a sports car doesn't make you a professional racer. Those are skills that require great understanding and body mechanics, involving far more than meets the eye. But hopefully, this article has given you some insight into how we judge the balance and usability of Indo-Persian weapons in SV.
Asante
Student of Gurudev Nidar Singh
Teaches Shastar Vidiya in London
Instagram @AsanteHunter
Facebook Page https://www.facebook.com/ShastarVidiyaBrixton/
Email Info@SVBrixton.com