The Secret Of The Persian Shamshir

[Timo Nieminen]

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]

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

Ian

[kai]

Hello Timo,

Thanks for chiming in!

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).

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]

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).

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]

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]

[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.