The Secret Of The Persian Shamshir

Ian · 31st January 2018, 05:01 PM

Hi Roland:

Thank you for starting this interesting discussion. It could go in a number of directions, but I hope we can pursue some of the science of sword use, as suggested nicely by Kai. I've not seen much engineering analysis of sword performance along the lines you describe. About the closest I've come is the physics of a baseball bat hitting a ball. Ten years ago I came across a small monograph on the topic of bat on ball, but I seem to have mislaid it. Perhaps someone else has seen it. It had a nice discussion of the forces in play and how these contributed to distortion of the shape of the ball and how far it traveled. It talked about the percussion point as being an important consideration of how effective the bat would be when connecting with the ball.

We had quite a lengthy discussion here in the past on a similar subject.

Your professional expertise is most welcome.

Ian.

Roland_M · 2nd February 2018, 05:43 PM

I was not able to answer earlier, I have a flu and I`m totally exhausted from the polishing of the Shamshir, sorry.

"If you simply hit the target with a direct blow, you won't achieve the cutting effect (and that's exIactly what happened in your test)."
Marius, you are right, a diagonal movement increases the effectiveness of the blow significantly. I also tried this out and diagonal movement on a slightliy curved blade make the cut go deeper by ~50%.
I made this thest also with some very sharp straight Indonesian short swords, no problem to cut the cartonage without diagonal movement. But never as deep as the Shamshir. The flexibility is also important, the M52 is pretty flexible, the Shamshir is much stiffer.

---

"Persian shamshirs are chiefly a cavalry weapon, and I think this is the main reason they look like this. The velocity of leading to impact comes mainly from the movement of the horse, not of the arm and is therefore much too powerful for a normal, man to man sword. In fact, I think it is usable, but not very effective as a duel weapon."

Yes, the Shamshir is clearly a battlefield and mainly cavalry weapon.
As a duell weapon the Shamshir is in a bad position against a rapier or long small sword for example.
But dont underestimate the Shamshir with boots on the ground!
Despite its weight the blade is astonishing fast and agile. The Shamshir is much faster than a straight sword of the same length and weight and even faster than a Kilij of the same dimensions. I cannot explain this in detail. So against a European longsword of same dimensions the Shamshir is in a relatively good position! Also against a Katana. The horse clearly got some influence on the speed of the blade but my arm is very much faster than a horse. I know there was a technique with the galloping horse forced in a fast 180° turn with its hind legs. This leads to a significant improvement of the blow. The Shamshir is also one of the most or the most effective cutting sword without a horse. There are videos on youtube with ancient ground techniques. But without question it is mainly a cavalry weapon.
As I said to Marius, diagonal movement on a slightliy curved blade make the cut go deeper by ~50%, maybe a little more. But without diagonal movement a sharp curved blade still cuts very well. You can do cuts with diagonal movement without a horse but it makes the blow much more difficult and complex.
https://www.youtube.com/watch?v=h8kquKxejSc
https://www.youtube.com/watch?v=mGBkrSL73kk

-----

"Also with a shamshir, there is a technique of bringing the sword around your head inside the curve quickly"
My technique in the sound file is leaned on a German Knight blow from medieval sources (the ox), which starts behind the head.

"I've not seen much engineering analysis of sword performance along the lines you describe."
Next thing I will try is a modern FEM (finite element method)-analysis. I did this last time ten years ago but if I`m successful, this would be a hard evidence. It is quite difficult to describe the Shamshir in senceful technical terms, because in our modern industry there is no thing like a Shamshir. I´m a specialist for aerodynamics, so your baseball would have been very interesting for me. If the ball is twisting during the flight, the aerodynamic is of great importance.

-------

"The European example seems to start with a straight blade (some distortion from the wide-angle lens photography?), the more strongly curved mid section, and a weak curve towards the tip (definitely not straight) - thus, I see at least 2 curves at play here."
It starts with a straight part because somehow you have to fix the handle.
And yes the last few inches before the point are a little straighter but this got no significant influence.
"how do you define separate curves? "
Sorry, this is obviously to see and I also highlighted it.
"BTW, have you determined the center of gravity, sweet spot, blade nodes, pivot points, etc.?"
Yes I detemined the center of gravity and what is a sweet spot?

"A comparison with the European "repro shamshir" will probably prove to be more interesting than with the M52 (the latter being an almost straight sword with a minor kink... )"
I clearly will not waste my money for a Cold Steel Shamshir. And what is the sence to compare a Shamshir with a Shamshir? This is why i said, the comparison is not 100% meaningful but we see complete destruction against a minor dent in the cartonage.

Roland

kai · 5th February 2018, 03:28 PM

Hello Roland,

Get well soon!

Quote:

It starts with a straight part because somehow you have to fix the handle.

Nah, that's only the tang: E. g. your real shamshir starts out with a (slightly) curved edge already. However, I don't believe this has any importance since this part of the blade won't do much cutting...

Quote:

how do you define separate curves?

Sorry, this is obviously to see and I also highlighted it.

That won't cut it as I tried to explain: If you prefer to dissect a continuum, you should define working criteria (when striving for reproducible results).

Quote:

Yes I detemined the center of gravity and what is a sweet spot?

The preferred point of contact is often referred to as sweet spot - since it combines several qualities, it is a more functional and less objective "definition" based on feel rather than science. It might be preferable to stick with well defined parameters as COP, etc.

Quote:

A comparison with the European "repro shamshir" will probably prove to be more interesting than with the M52 (the latter being an almost straight sword with a minor kink... )

I clearly will not waste my money for a Cold Steel Shamshir. And what is the sence to compare a Shamshir with a Shamshir?

Well, I believed the Euro "shamshir" you posted was yours, too. That one seems to be a real sword - no need to get a modern repro of questionable ergonomics...

Regards,
Kai

Timo Nieminen · 5th February 2018, 10:13 AM

Quote:

Originally Posted by Ian

Ten years ago I came across a small monograph on the topic of bat on ball, but I seem to have mislaid it. Perhaps someone else has seen it. It had a nice discussion of the forces in play and how these contributed to distortion of the shape of the ball and how far it traveled. It talked about the percussion point as being an important consideration of how effective the bat would be when connecting with the ball.

For bats and rackets, the centre of percussion certainly contributes to the sweet spot. For swords where the rotation is about the grip (or at least, the wrist), like sabre styles where the sword is held in front of the body, and the hand stays fairly still, it's also important for where the sweet spot is.

However, for swords where the rotation is about the shoulder (i.e., the whole arm moves), it isn't particularly important for impact. It's still important for handling, because when you move the hilt sideways, the centre of percussion will want to stay still. Thus, if you have the COP at the tip, the tip will stay still, and you get very nice point control (hand-and-a-half longswords and jian are often balanced like this). Or for swords that are expected to be in contact with an opponent's blade or shield (like arming swords for sword and buckler, or rapier), you can have the COP at the expected point of contact for easy rotation of the sword about that point.

But since a shamshir isn't used for hand-stationary cuts but rather for slicing draw cuts from the shoulder, and isn't used like a jian or rapier, or arming sword with buckler, I don't think the location of the COP matters, and I'd expect either of two things: (a) the COP at about 8" from the tip, because that's common on a wide variety of sabres (especially Western, but also common on talwars and katanas and other Asian sabres), or (b) the COP to be just wherever, with no systematic placement (which, as far as I can tell, is how the COP is placed on most Chinese dao).

PS: the pendulum test (i.e., finding the position of the centre of oscillation (which is the same as the centre of percussion)) is probably the best way to find the location of the COP of a shamshir. I don't trust the waggle test of very curved blades.

[I should put together something systematic and detailed on the COP. If time permits ...]

Ian · 5th February 2018, 02:21 PM

Thank you Roland. I look forward to more discussion of the COP.

Ian

kai · 5th February 2018, 03:02 PM

Hello Timo,

Thanks for chiming in!

Quote:

But since a shamshir isn't used for hand-stationary cuts but rather for slicing draw cuts from the shoulder, and isn't used like a jian or rapier, or arming sword with buckler, I don't think the location of the COP matters, and I'd expect either of two things: (a) the COP at about 8" from the tip, because that's common on a wide variety of sabres (especially Western, but also common on talwars and katanas and other Asian sabres), or (b) the COP to be just wherever, with no systematic placement

For pre-Qajar shamshir, I thumbed through Manouchehr's "Arms and Armor from Iran" and the COP seems to center at about 11 inches (from sword tip) within a fairly narrow range of approx. +/- 1 inch (regardless of curvature and not correcting for differences in total sword length).

Quote:

the pendulum test (i.e., finding the position of the centre of oscillation (which is the same as the centre of percussion)) is probably the best way to find the location of the COP of a shamshir. I don't trust the waggle test of very curved blades.

Yes, the waggle test with straight blades already needs skill/experience and strongly curved pieces will present a major obstacle to get reliable data from!

If a strongly curved blade has a medial ridge (or other features at the contact point which favour movement in a second dimension), is very thick or elastic, even the pendulum test might prove to be real challenge though.

Regards,
Kai

Timo Nieminen · 6th February 2018, 09:58 AM

Quote:

Originally Posted by kai

For pre-Qajar shamshir, I thumbed through Manouchehr's "Arms and Armor from Iran" and the COP seems to center at about 11 inches (from sword tip) within a fairly narrow range of approx. +/- 1 inch (regardless of curvature and not correcting for differences in total sword length).

I can't tell for sure from the description whether he gives the centre of percussion (i.e., the centre of percussion as defined by all non-sword people) or the closest-to-the-tip node of vibration (which is often called the COP by sword people).

Quote:

Footnote 51, pg 138:
COP (center of percussion) is the point where the saber has its highest cutting power. To measure this point, one holds the grip of the sword or saber in his right hand. Then, a strike is given by the palm of the left hand to the right hand, which is holding the saber. The blade needs to be carefully watched. The COP is the center or place of the blade that has the least vibration.

The key to what is actually measured is that last word, "vibration". I think the measurement is a measurement of the node of vibration, but I'm not certain.

Roland_M · 8th February 2018, 12:57 PM

Quote:

Originally Posted by Timo Nieminen

I can't tell for sure from the description whether he gives the centre of percussion (i.e., the centre of percussion as defined by all non-sword people) or the closest-to-the-tip node of vibration (which is often called the COP by sword people).

The key to what is actually measured is that last word, "vibration". I think the measurement is a measurement of the node of vibration, but I'm not certain.

Sweet spot and center of percussion are terms from Baseball. I have serious doubts, that we can use such terms for describing swords. Because the specification is quite different.
At least a Baseball bat is no static device.

Also the point of balance means not much or nothing. For example the POB of the shamshir (1kg) is ~18 cm away from the guard. On my European rapier (1kg) the POB is ~5cm away from the guard. But the Shamshir is clearly mor agile and more flexible to use than the rapier. So what does the POB says?

Theory (!): In a two dimensional coordinate system we have two axes, the x and y-axis.
If we describe the POB we use the lengthwise axis, which is normally the x-axis. But the POB on the y -axis is also important! The POB should be as close to the cutting edge as possible! This leads to a more stable blow. Maybe this is one reason for the 38 fullers, next to a lower weight.

I found out for myself, that all modern technical terms are pretty useless to describe a sword. So I tried to avoid modern technical terms in my text.

Tons of technical descriptions are nothing compared to a real test blow.

I tried out the usability of many different sword types (normally without cutting tests), so I'm pretty experienced in this field. Nowadays I can hold a sword, make some blows in the air and I can say, what it is designed for (for example once I tried out a long Afghan Kyber knife/sword and it was clear within seconds that this is a cutting weapon, despite its sharp and long point. Later I found out, that this is absolutely true).

My concluison: Modern technical terms are between not ideal and useless to describe an ancient edged weapon.

Roland

Norman McCormick · 8th February 2018, 06:34 PM

[QUOTE=Roland_M]Sweet spot and center of percussion are terms from Baseball. I have serious doubts, that we can use such terms for describing swords. Because the specification is quite different.
At least a Baseball bat is no static device.

Hi Roland,
Centre of Percussion is a well known term when applied to swords. Many Victorian military swords are marked as such with a C and P clearly visible on the spine. I in fact have a Wilkinson Cavalry Officers sword, manufacture date 1877, with such markings.
Regards,
Norman.

31st January 2018, 05:01 PM	#1
Ian Vikingsword Staff Join Date: Dec 2004 Location: The Aussie Bush Posts: 4,363	Good idea Roland Hi Roland: Thank you for starting this interesting discussion. It could go in a number of directions, but I hope we can pursue some of the science of sword use, as suggested nicely by Kai. I've not seen much engineering analysis of sword performance along the lines you describe. About the closest I've come is the physics of a baseball bat hitting a ball. Ten years ago I came across a small monograph on the topic of bat on ball, but I seem to have mislaid it. Perhaps someone else has seen it. It had a nice discussion of the forces in play and how these contributed to distortion of the shape of the ball and how far it traveled. It talked about the percussion point as being an important consideration of how effective the bat would be when connecting with the ball. We had quite a lengthy discussion here in the past on a similar subject. Your professional expertise is most welcome. Ian. Last edited by Ian; 31st January 2018 at 05:12 PM.

2nd February 2018, 05:43 PM	#2
Roland_M Member Join Date: Aug 2014 Location: Germany Posts: 525	I was not able to answer earlier, I have a flu and I`m totally exhausted from the polishing of the Shamshir, sorry. "If you simply hit the target with a direct blow, you won't achieve the cutting effect (and that's exIactly what happened in your test)." Marius, you are right, a diagonal movement increases the effectiveness of the blow significantly. I also tried this out and diagonal movement on a slightliy curved blade make the cut go deeper by ~50%. I made this thest also with some very sharp straight Indonesian short swords, no problem to cut the cartonage without diagonal movement. But never as deep as the Shamshir. The flexibility is also important, the M52 is pretty flexible, the Shamshir is much stiffer. --- "Persian shamshirs are chiefly a cavalry weapon, and I think this is the main reason they look like this. The velocity of leading to impact comes mainly from the movement of the horse, not of the arm and is therefore much too powerful for a normal, man to man sword. In fact, I think it is usable, but not very effective as a duel weapon." Yes, the Shamshir is clearly a battlefield and mainly cavalry weapon. As a duell weapon the Shamshir is in a bad position against a rapier or long small sword for example. But dont underestimate the Shamshir with boots on the ground! Despite its weight the blade is astonishing fast and agile. The Shamshir is much faster than a straight sword of the same length and weight and even faster than a Kilij of the same dimensions. I cannot explain this in detail. So against a European longsword of same dimensions the Shamshir is in a relatively good position! Also against a Katana. The horse clearly got some influence on the speed of the blade but my arm is very much faster than a horse. I know there was a technique with the galloping horse forced in a fast 180° turn with its hind legs. This leads to a significant improvement of the blow. The Shamshir is also one of the most or the most effective cutting sword without a horse. There are videos on youtube with ancient ground techniques. But without question it is mainly a cavalry weapon. As I said to Marius, diagonal movement on a slightliy curved blade make the cut go deeper by ~50%, maybe a little more. But without diagonal movement a sharp curved blade still cuts very well. You can do cuts with diagonal movement without a horse but it makes the blow much more difficult and complex. https://www.youtube.com/watch?v=h8kquKxejSc https://www.youtube.com/watch?v=mGBkrSL73kk ----- "Also with a shamshir, there is a technique of bringing the sword around your head inside the curve quickly" My technique in the sound file is leaned on a German Knight blow from medieval sources (the ox), which starts behind the head. "I've not seen much engineering analysis of sword performance along the lines you describe." Next thing I will try is a modern FEM (finite element method)-analysis. I did this last time ten years ago but if I`m successful, this would be a hard evidence. It is quite difficult to describe the Shamshir in senceful technical terms, because in our modern industry there is no thing like a Shamshir. I´m a specialist for aerodynamics, so your baseball would have been very interesting for me. If the ball is twisting during the flight, the aerodynamic is of great importance. ------- "The European example seems to start with a straight blade (some distortion from the wide-angle lens photography?), the more strongly curved mid section, and a weak curve towards the tip (definitely not straight) - thus, I see at least 2 curves at play here." It starts with a straight part because somehow you have to fix the handle. And yes the last few inches before the point are a little straighter but this got no significant influence. "how do you define separate curves? " Sorry, this is obviously to see and I also highlighted it. "BTW, have you determined the center of gravity, sweet spot, blade nodes, pivot points, etc.?" Yes I detemined the center of gravity and what is a sweet spot? "A comparison with the European "repro shamshir" will probably prove to be more interesting than with the M52 (the latter being an almost straight sword with a minor kink... )" I clearly will not waste my money for a Cold Steel Shamshir. And what is the sence to compare a Shamshir with a Shamshir? This is why i said, the comparison is not 100% meaningful but we see complete destruction against a minor dent in the cartonage. Roland

5th February 2018, 02:21 PM	#5
Ian Vikingsword Staff Join Date: Dec 2004 Location: The Aussie Bush Posts: 4,363	Thank you Roland. I look forward to more discussion of the COP. Ian

8th February 2018, 06:34 PM	#9
Norman McCormick Member Join Date: Oct 2007 Posts: 1,613	[QUOTE=Roland_M]Sweet spot and center of percussion are terms from Baseball. I have serious doubts, that we can use such terms for describing swords. Because the specification is quite different. At least a Baseball bat is no static device. Hi Roland, Centre of Percussion is a well known term when applied to swords. Many Victorian military swords are marked as such with a C and P clearly visible on the spine. I in fact have a Wilkinson Cavalry Officers sword, manufacture date 1877, with such markings. Regards, Norman.