Letting Go of the Korean Target

I love the Korean target face.  I think it adds to the flamboyance and style that makes our sport so different from standing 70m from a target and shooting endless identical arrows at a boring circular target.

Unfortunately, much of the world is not set up for the Korean target.  We were very lucky that WHAF, in their ongoing kindness and support, sent us some beautiful targets ready for our national championships last year.  We had bosses of the correct size and everything went well.  Many people do not have ready access to big square target bosses, even if WHAF were to send faces to everybody who wanted them.  In particular, we were informed by our American friends that almost all bosses over there are circular and either 80cm or 120cm (the two most common sizes for FITA archery targets).  Pythagoras told us many centuries ago that the corner of a 90cm Korean target face is some 63.6cm from the centre, whereas the edge of a 120cm boss is only 60cm from the centre.

This caused us some difficulty when establishing a grading system.  Clearly for a system to have any meaning you had to be comparing like with like.  If one person has a bigger target than another then how do you compare their scores?  We needed to have either everybody using the same scores or a way of comparing scores on different targets accurately and fairly.

The general feeling was that in America, and possibly many other places, use of the Korean target face would restrict the number of people able to use the system we were trying to establish.  We had to allow people to use the ubiquitous FITA target faces.

My feeling was that this was not a major problem.  It should not be beyond the wit of man to devise a system of converting zones 1-5 in a square of known edge length to zones 1-5 in a circle of known diameter.  It should simply be a matter of working out how much bigger the square is than the circle.  Each zone should decrease proportionately since they are marked by a given fraction of the edge/diameter.

As it turns out, this cannot be done after all.  The Korean target faces do not have zones of equal edge length.  Measuring from the centre towards one edge, the 5 zone is 12cm, 4 and 3 are 7cm each and 2 and 1 are 9cm each.  A direct comparison is beyond my abilities.

I am still pondering ways to get around this problem nothing in the whole system has caused me more mental turmoil than abandoning the Korean target face.  If anyone can think of a mathematical model that will allow a direct comparison then please get in touch.  In the alternative I intend to keep a close eye on scores shot under each system in the hope of working out a rough (but as accurate as possible) conversion based on a mixture of geometry and statistics.  I will not give up those wonderful targets without a fight!

4 thoughts on “Letting Go of the Korean Target

  1. Hi Dan. Maybe I’m thinking too simple, but why not take all the measurements of a Fita target and give it the Korean colours and put a tigerhead in the middle, in other words: repaint them?

    • Hi Claire,
      That certainly could be done, although the FITA is round and the Korean square. At EOCHA and Al Faris they use a variant on the Korean target that is not quite the same as the WHAF targets. I think that they could probably be converted easily.
      The problem is that we would like to allow people to use the official WHAF targets but this is not possible as long as the WHAF targets have those awkward measurements.
      I may well look at making some square Korean targets that can be use for a conversion. Of course the square target will be bigger than the round one so there will be a slight difference in how easy it is to get your bonus points for hitting all targets and you time bonus for hitting at least one…

      It can’t just be simple, can it?

  2. You have to specify a relation between measurements of one target and those of another. It seems to me that you shouldn’t specify a relation between linear measurements (your 12 cm, 7 cm, 9 cm), but rather between measurements of area. For instance, a 12 cm square is actually 144 cm^2. You might equate such a square to a circle of radius 6.77 cm. Or you might say that hitting one of these shapes is harder than hitting another (in my own archery, I find the vertical deviation to be larger than the diagonal deviation, so I’d prefer circles to squares), so you wish to introduce a small (say 5%) handicap. When comparing outer rings, you might want to compare entire areas, or perhaps net areas (that is, after subtracting the areas of inside rings).

    There are going to be some judgment calls no matter what, but if you’re reasonably systematic about the effort it doesn’t seem impossible. On the other hand, is a target with a 6.77 cm bullseye any easier to source than a square target? Perhaps the best solution is to develop conversion tables, so that you could say “a score of 100 on this target equates to a score of 115 on that target”. If you had enough archers with access to both types of target, who were committed to meticulous record-keeping and well-controlled test procedures, you could even develop such tables empirically.

    Or perhaps I’ve misunderstood some obvious point. If so please correct me.

    • You are certainly right that we need to look at area rather than length, but the one follows from the other. If you have a 90cm square target divided up so that from the centre to the edge of the 5 is 9cm, then a further 9cm to the edge of the 4 and so on, then the areas will be as follows:
      5: 18^2cm = 324
      4: 36^2 – 18^2 = 972
      3: 54^2 – 36^2 = 1620
      2: 72^2 – 54^2 = 2268
      1: 90^2 – 72^2 = 2916

      On a circular FITA 80cm target the areas are:
      5: 8^2pi = 64pi = 201.06
      4: 16^2pi – 8^2pi = 192p = 603.19i
      3: 24^2pi – 16^2pi = 320pi = 1005.31
      2: 32^2pi – 24^2pi = 448pi = 1407.43
      1: 40^2pi – 32^2pi = 567pi = 1781.28

      The ratio of the area of the 1 zone on the square and round targets is therefore = 324/201.06 = 1.61. This is the same as the ratio between the every other equivalent scoring zone, as well as to the target as a whole (90^2 – 40^2 pi = 1.61).

      In other words, if the linear measurements are even within the targets then the areas will come out to have the same ratio. The plan would then be to apply that ratio to the score that you achieve (so a score of 100 on a Korean target would be a score 161 on a FITA).

      Claire has been doing some work on this and has created a Korean face where the measurements are as I have outlined. We are now looking into getting some printed, which would allow us to convert.

      The complication then becomes the fact that you are more likely to pick up bonus points for speed and/or multiple hits if you use Korean targets, since you are more likely to hit the target. This needs to be factored in to some extent, although I personally don’t think it needs to be too precise since for postal matches everyone would use the same face and the gradings are not so finely tuned or so important that we need to get the conversion overly complicated.

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