Deflection and the cubic diagonal of a narrow rectangular prism

[lansao]

So that title is super long winded and I apologize. Also apologize if I'm posting too much and you all think I should take a breather, haha. Lots on my mind lately and just want to throw stuff out as it comes up.

One thought has been the use of cubic diagonals (of narrow rectangular prisms) as an approach to thinking about how deflection works and at what angles. Has anyone else found themselves using this idea when helping to explain hand positions like Tan Sao, Bong Sao, Fook Sao, and Lan Sao (or other analogies)?

 

[hoshin1600]

I'm pretty cerebral in how I approach martial arts even though I'm not a Chun guy. I'm interested to hear your concepts.

 

[lansao]

I'm pretty cerebral in how I approach martial arts even though I'm not a Chun guy. I'm interested to hear your concepts.

Hey, happy to share my thoughts. Can't take credit for the use of the property in fighting arts but wonder if we've ever had this particular discussion. We often talk about angles of deflection in Wing Chun. There's a sweet spot with that angle where if you come in with too narrow of an angle, your deflection is great but you're not filling enough space. If you fill too much space, you're not creating an angle of deflection. I struggled with finding that sweet spot until I landed on an analogy from geometry. I figured it out for our bong sao first (may not be the way we all train it but I'm sure some of us do). If I mark up the image above with a few labels it helps make the case.
.

This is a little scattered but in the image above, line A represents the direction of an incoming strike from an opponent's left arm. It runs parallel with the long side of the rectangle highlighted in blue. The defender side steps/strafes slightly along line D while rotating his/her right arm's elbow along the direction of line C (the wrist is at the bottom left corner of the rectangle highlighted in blue) so that line B (representing the forearm) can impact line A with just enough force to set it's trajectory off course (toward the same corner line C is aiming for). It's a lot like nudging a comet off course, surprisingly little effort/energy needed to accomplish that (relative to the mass/velocity of the incoming object). Bong Sao is a little obscure (although I maintain it behaves a lot like a shoulder role but with your forearm). That obscurity is what led me to dig into this math and that's when I realized these diagonals are everywhere in the art. Flip this diagram upside down and you get Tan Sao's deflective angle, same thing with the capping punch, and other deflections.

Need to head out for work but will share a mockup of Tan Sao in a bit too.

 

[hoshin1600]

i understand your concept with different vectors changing the angle of the punch. is this how YOU use Bong Sao, as a deflection? like i said im not a wing chun practitioner but from my estimation using Bong Sao to actually change the course of the attacking arm is not effective. the issue i see is that a deflection application is not taking into account the larger picture of the rest of the human body and its mechanics in relationship to the subsequent actions within the fight. it would be much more effective to use the Bong Sao arm as a sensor to feel where the attackers are is in relationship to my own body and the brain can then use that sensory input to move my body off of the attacking vector line. thus there is no deflection and the attackers arm remains almost on its original vector but my body will not be there to be hit, my arm will then roll over the attackers arm for my own counter. this is efficient . it has been my experience that a deflection needs more stability and rigidity in the arm and will slow a counter strick down enough to lose the opportunity.

just my thoughts but as far as the math and your concept seems solid.

 

[lansao]

i understand your concept with different vectors changing the angle of the punch. is this how YOU use Bong Sao, as a deflection? like i said im not a wing chun practitioner but from my estimation using Bong Sao to actually change the course of the attacking arm is not effective. the issue i see is that a deflection application is not taking into account the larger picture of the rest of the human body and its mechanics in relationship to the subsequent actions within the fight. it would be much more effective to use the Bong Sao arm as a sensor to feel where the attackers are is in relationship to my own body and the brain can then use that sensory input to move my body off of the attacking vector line. thus there is no deflection and the attackers arm remains almost on its original vector but my body will not be there to be hit, my arm will then roll over the attackers arm for my own counter. this is efficient . it has been my experience that a deflection needs more stability and rigidity in the arm and will slow a counter strick down enough to lose the opportunity.

just my thoughts but as far as the math and your concept seems solid.

Totally is! So when a jab comes in, I'm not thinking of whacking the arm so hard with the bong sao that it moves them away from me. I'm side stepping a short distance while rotating the bong sao into place so that the punch is missing my head with ~4 inches of clearance. The deflection happens when the bong arm makes contact early into its rotation, the rotational force of the forearm helps to alleviate/avoid any direct wedging that might happen. I wouldn't want to jam/wedge the bong sao into the incoming punch, but catch it with the rotation of the forearm to assist in sending the arm up and to the left (assuming it's my right bong sao off a left jab). You can totally use bong sao when already making contact to redirect, but it can serve really effectively as a linear deflection with little effort (just have to find the sweet spot) to protect you and help establish contact to go from there.

Generally however, it falls along what we call our second ring of protection (maybe specific to my school of thought) so I might not want to lead with it over Pak/Tan etc. First ring is lead hand wrist, second is lead elbow rear wrist, third is rear elbow (often off a lead t-step). Lots of jargon in there but happy to lay it out too if you're curious.

 

[lansao]

is this how YOU use Bong Sao, as a deflection?

Oh and to make sure I answer this question: Yes, totally. This is in many ways the primary way I use bong sao in addition to redirection for stand-up grappling/chi sao.

 

[PiedmontChun]

The angle and timing of something such as a Pak Sau is very important. Too close to their wrist and they still smash in and around your Pak. Likewise, too far up to the elbow and there is not sufficient deflection. Tan Sau is often a first action, combined with a punch, and the angle is very important. Drilling and then more dynamic lat sau helps find and train that sweet spot.
For Bong Sau though, and maybe this is my LT/WT leaning training, but it is reactionary. I never think "Bong Sau", it just happens when there is an obstruction.

 

[lansao]

The angle and timing of something such as a Pak Sau is very important. Too close to their wrist and they still smash in and around your Pak. Likewise, too far up to the elbow and there is not sufficient deflection. Tan Sau is often a first action, combined with a punch, and the angle is very important. Drilling and then more dynamic lat sau helps find and train that sweet spot.
For Bong Sau though, and maybe this is my LT/WT leaning training, but it is reactionary. I never think "Bong Sau", it just happens when there is an obstruction.

That’s interesting. What this geometry is telling me is that my bong operates a lot like an upside down tan. It deflects up and opposite the arm while tan deflects down and opposite the arm.

In general I don’t think about hand positions as being very different from each other anymore either. They are all still my arms moving in weird deflective diagonal ways. But I find sometimes stepping out of that continuous analysis space and into a more discrete one (like from sound waves to music notation) helps me find patterns that I can test in practice.

Like, the reality is we deal in sound waves but the music notation makes good scaffolding for learning to navigate them.

 

[hoshin1600]

just to be clear i am not really questioning whether Bong Sao works. i am probing into whether or not your geometry analogy is accurate.
the key factor in this is ....

force = change in momentum
Time taken for change


the attacking arm has momentum, a defection is a change in the momentum. the longer the time of contact, the smaller the force that is needed to deflect it.
as you explained in your second post ,,you make contact then using a rotational force you divert the attacking arm, thus more time on the target. if you shorten the time of contact then you would need more force. but i was also thinking about the rigidity of the defending Bong sao arm. you model seems to be based on a 1 to 1 ratio of rigidity between arms.
example;
if a ball is angle bounced off of a brick wall the contact time is short but the wall has a 100% rigidity. if you try to bounce the ball off a hanging sheet there is close to 0 % rigidity and the ball will not bounce or deflect.
that being said i am questioning how much rigidity and time will it cost to actually deflect the arm VS using the arm on arm contact as an axis point in time and space that you would rotate around for a counter punch. i believe that a sacrifice of not actually deflecting the arm will allow a faster better counter punch, but the opposite would be true as well more defection would mean a slower counter. using the Bruce Lee count/ beat concept you would be making a choice between one beat or two beats.
so if the attackers arm had way more mass then mine i would need more defection that needs to be done with time or rigidity

 

[jobo]

So that title is super long winded and I apologize. Also apologize if I'm posting too much and you all think I should take a breather, haha. Lots on my mind lately and just want to throw stuff out as it comes up.

One thought has been the use of cubic diagonals (of narrow rectangular prisms) as an approach to thinking about how deflection works and at what angles. Has anyone else found themselves using this idea when helping to explain hand positions like Tan Sao, Bong Sao, Fook Sao, and Lan Sao (or other analogies)?

I. Not sure that refraction and deflection have the same geometry ? You might be better off with a pool table analogy ?

 

[lansao]

just to be clear i am not really questioning whether Bong Sao works. i am probing into whether or not your geometry analogy is accurate.
the key factor in this is ....

force = change in momentum
Time taken for change


the attacking arm has momentum, a defection is a change in the momentum. the longer the time of contact, the smaller the force that is needed to deflect it.
as you explained in your second post ,,you make contact then using a rotational force you divert the attacking arm, thus more time on the target. if you shorten the time of contact then you would need more force. but i was also thinking about the rigidity of the defending Bong sao arm. you model seems to be based on a 1 to 1 ratio of rigidity between arms.
example;
if a ball is angle bounced off of a brick wall the contact time is short but the wall has a 100% rigidity. if you try to bounce the ball off a hanging sheet there is close to 0 % rigidity and the ball will not bounce or deflect.
that being said i am questioning how much rigidity and time will it cost to actually deflect the arm VS using the arm on arm contact as an axis point in time and space that you would rotate around for a counter punch. i believe that a sacrifice of not actually deflecting the arm will allow a faster better counter punch, but the opposite would be true as well more defection would mean a slower counter. using the Bruce Lee count/ beat concept you would be making a choice between one beat or two beats.

No worries, it's cool. This is helpful discussion. You can experiment with this using sticks. You can create the cubic diagonal with one stick, and slide another along that strike line in the diagram above. You'll find it wants to ride up and away almost forming an X between both sticks. I'll see if I can post a video about it tonight. Will also see if I can have a student punch for me Tuesday morning to demonstrate.

 

[lansao]

I. Not sure that refraction and deflection have the same geometry ? You might be better off with a pool table analogy ?

Rectangular prism or rectangular cuboid are just names of the shape I know "prism" is normally associated with light refraction but it was between rectangular cuboid or orthotope at the time. Felt that "prism" would make the sentence less cubey.

"A three-dimensional orthotope is also called a right rectangular prism, rectangular cuboid, or rectangular parallelepiped. A special case of an n-orthotope, where all edges are equal length, is the n-cube."

Hyperrectangle - Wikipedia

In retrospect I guess "hyperrectangle" would have accomplished the same.

 

[lansao]

No worries, it's cool. This is helpful discussion. You can experiment with this using sticks. You can create the cubic diagonal with one stick, and slide another along that strike line in the diagram above. You'll find it wants to ride up and away almost forming an X between both sticks. I'll see if I can post a video about it tonight. Will also see if I can have a student punch for me Tuesday morning to demonstrate.

To add to this, you'll also find that the end of the striking stick/direction it's pointing moves pretty dramatically with very little force/movement from the bong stick.

 

[pdg]

if a ball is angle bounced off of a brick wall the contact time is short but the wall has a 100% rigidity. if you try to bounce the ball off a hanging sheet there is close to 0 % rigidity and the ball will not bounce or deflect.

Well...

A ball will bounce off a wall, yes. A ball won't bounce of a sheet.

But, say it's a tennis ball and a bedsheet - the trajectory of the ball will very definitely be altered - it will be deflected.

Off a wall could be considered linear, whereas 'off' a sheet is more partially parabolic. The sheet will yield somewhat but the ball will get deflected and it's energy dispersed.

Now up it, there comes a point where absolute rigidity leads to destructive failure - wrecking ball. It's a ball, but bounce off a wall it does not.

So with deflecting an incoming punch, you can think bounce, but that might lead to break - yours or theirs though?

Think parabolic dispersion, yield yet deflect.

 

[lansao]

Well...

A ball will bounce off a wall, yes. A ball won't bounce of a sheet.

But, say it's a tennis ball and a bedsheet - the trajectory of the ball will very definitely be altered - it will be deflected.

Off a wall could be considered linear, whereas 'off' a sheet is more partially parabolic. The sheet will yield somewhat but the ball will get deflected and it's energy dispersed.

Now up it, there comes a point where absolute rigidity leads to destructive failure - wrecking ball. It's a ball, but bounce off a wall it does not.

So with deflecting an incoming punch, you can think bounce, but that might lead to break - yours or theirs though?

Think parabolic dispersion, yield yet deflect.

My Sifu would say, and my experience confirms, that it feels almost like you’re filleting their arm with yours.

 

[pdg]

My Sifu would say, and my experience confirms, that it feels almost like you’re filleting their arm with yours.

I've become much more circular with my blocking in recent months, tending more and more away from 'bounce'.

I've had (minor) complaints from almost every other student about "blocking too hard" during partner drills, and a few of them started putting their sparring shinguards on their forearms if they knew I was to possibly be their opponent...

It's become more entertaining to deflect differently and have much more effect on their balance.

 

[lansao]

I've become much more circular with my blocking in recent months, tending more and more away from 'bounce'.

I've had (minor) complaints from almost every other student about "blocking too hard" during partner drills, and a few of them started putting their sparring shinguards on their forearms if they knew I was to possibly be their opponent...

It's become more entertaining to deflect differently and have much more effect on their balance.

Sounds great, why not? Unification of movement right there.

 

[pdg]

Sounds great, why not? Unification of movement right there.

It's taught as hard blocks, which I'm not denying can be effective. But I evolved my interpretation to include the option of effective softness.

To paraphrase from this thread - sometimes it's best to be the wall, other times you're better off if you can be the sheet

 

[hoshin1600]

Now up it, there comes a point where absolute rigidity leads to destructive failure - wrecking ball. It's a ball, but bounce off a wall it does not

true but maybe not the greatest analogy since the wrecking ball has more mass.
if you try to use Bong Sao on hulk hogan his mass will bull right thru you

 

[hoshin1600]

But, say it's a tennis ball and a bedsheet - the trajectory of the ball will very definitely be altered - it will be deflected.

yes it wont bounce but it will be in contact with the sheet for a very long duration.
there are some main components here and there is a trade off needed no matter how you look at it