Stroboscopic photo of a wink being potted in the game of tiddlywinks The North American Tiddlywinks Association
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Editor's Note:

Following is Rick Tucker's term project for the MIT Strobe Projects Laboratory course (known as 6.163) in Fall 1979.   Charlie Miller was the instructor for the course, and Doc Edgerton gave several lectures and oversaw the labs and MIT's Strobe Alley at large.  Rick introduced his parents to Doc Edgerton one day in the Fall of 1979, to the pleasure of all.

Be sure to see other strobe photos from Rick Tucker.

- Rick Tucker


Tiddlywinks Photography

6.163 Strobe Project Laboratory Project Report Richard W. Tucker, 13 December 1979
 
C. E. MILLER

DEC 13 1979

REF. TO
FILE

Summary

The primary aim of this project was to see what actually occurs in both successful and unsuccessful shots in the game of Tournament Tiddlywinks.  I tried to relate the various factors involved in making a shot with the results shown in photographs.

The tiddlywinks shots I photographed were basic shots--potting and squopping; also the commonly used Bristol and boondock; and specialized shots such as the gromp and Good shot.

Equipment List


E23-15, Dec 1979 Tucker shooting winks in strobe lab 50dpi DM.JPG (69432 bytes)
© 1979 Richard W. Tucker.  All Rights Reserved

Rick Tucker in Doc Edgerton's strobe lab, Building 10 (the upper fourth floor), MIT
f/11, 10 sec, Setup with EG&G 553 multiflash, 120 fps, Minolta XG7 f/11
E23/15, printed 13 Dec 1979


Background

A little background about the form of Tournament Tiddlywinks is necessary.  The official game is played on a 1/8" by 3' by 6' white felt mat by four players.  At the center of the mat is a red pot, 1 7/16" tall, 1 3/8" in diameter at the base, and 2" in diameter at the top.  There are 2 large winks (7/8" = 22mm in diameter) and 4 small winks (5/8" = 16 mm in diameter) of different colors for each players.  These winks are played by shooting them with a squidger, which is a disc from 1 to 2 inches in diameter.  Two players play as partners against the other two.  The game is scored at the end of a 25 minute time period plus 5 rounds more for each player.  The game involves controlling territories by sending winks into tactically important areas, and by squopping opponent winks--that is, covering them.  A wink that is squopped may not be shot until it is freed.  It may be freed by knocking off the wink that is controlling it.  However, it is easier in general to send a wink to rescue the squopped on, by covering the opponenet squopper.  Once a player's wink is over anorther wink, the player has the option of following throught on his or her shot, after stroking the player's own wink first, to stroke any winks below.  Over the past 25 years of Tournament Tiddlywinks, strategies and shot making have improved to a state where squopping and manipulating piles of squopped winks occupy all or nearly all of a game, while potting--which is propelling a wink into the pot--occurs primarily at the end, even though a wink in the pot is worth more when the game score is counted.  My interest in photographing tiddlywinks covers most  of the shots found in modern tournament play.

Setup & Procedure

I initially used the Sony Video Motion analyzer and the vidicon tube camera to record on the video disc.  Since a tiddlywinks shot takes less than a second (some may be more), the 10 second recording capacity and 60 field per second recording rate, and 1/500 second shutter speed seemed adequate for my initial purpose of seeing what was happening during a tiddlywinks shot.  While videodisc analysis of shots provided insights to the actual motions, the afterimage of the camera, the lack of fine resolution, and the limit of 60 views per seconds provoked me to work more with multiflash photography    The freedom of choosing any sampling rate, the fine grain resolution of film, and the very short duration of each sampling produces excellent results in studying tiddlywinks shots.

I tried the 1540 Strobolume triggered with a photoelectric pickoff aimed at a calibrated 1531-A Strobotac, but I found the EG&G 553 Multiflash system better suited due to the broader angle of output and ease in triggering.

I placed the 553 lamp in several locations in shooting sessions.  In earlier ones, it was placed at a 90° angle from the camera to the subject.  In a later one, I placed it behind the camera. (*: The 553 was always on low output, usually 120 flashes per second, usually for .75 seconds.)

I originally calculated the guide number for Plus-X (ASA 125) with a magnification factor of 1:

A * d = ((BCPS * S / c)^0.5)/(m+1) = ((400 * 125/20)^0.5)/2 = 22.3 guide number

I placed the lamp 2.8 feet from the subject, and tried f/8, f/11, and f/16.  I found that f/11 was appropriate for a good exposure.  When I used Ektachrome 200, I recalculated the guide number taking into account the f/11 with 2.8 feet, and go a guide number of 40.  For Ektachrome 200, I used a distance of 3.5 feet and f/11 (f/8 for very close shots).

While the tournament game of tiddlywinks is played on a white or light gray felt mat, such a background would be bad for multiflash photography.  As I had a dark green sample of felt, I used it in the early shooting sessions.  While the photographic results with this playing surface were reasonable in exposure, I felt improvements could be made.  I decided to take the pieces of thin black velvet I was using for a background (when the large ones mounted on wood would not do) and place them over my mat.   I found that the velvet did not noticeably affect any shots, and furthermore, results were better.

I decided that my hand and forearm were obscuring parts of a number of shots.  I went to search for thin black cotton gloves to try, and found them hard to locate.   My mother gave me some, though.  While they were small and slippery, and tiddlywinks shots require precise control of the squidger on winks, results were well worth the extra care to make shots, and the increased number of missed shots.  The setup for one of the middle shooting sesisons is shown in the photograph on the next page. [@@@]

Results and Analysis

I will present my most interesting photographs and describe what they show.

1. Potting.

Potting is stroking a wink with a squidger with the aim of propelling it into the pot.

There are different styles of potting winks:

a. The squidger is angled up toward the pot.  Nearly all players shoot this way.   Most stand so that the pot is betwen the wink and the player's body, the three forming a straight line, so the direction of the shot is toward the player.

b. Some pot with a 90° angle between the player, pot, and wink.

c. Almost never do players shoot with the wink between the pot and the player, so that the shot is away from the player.

In order to produce better multiflash photographs, I switched to the latter orientation to get my arm out of the picture.

For potting, most players hold the squidger angled up toward the pot.  However, Slide 3/5 shows a different method of potting, where the wink is sent away from the player as described in c, above. However, here the squidger is held as one would ordinarily squop; that is, angled down toward the target.  As in ordinary squop strokes, the wink does not flip much, and has a low trajectory, a line drive.  While the wink bounced on the rim and went in, it hs a lesser likelihood of bouncing out with this method than if it had been shot with the squidger angled up.  However, the low trajectory of the down-angled pot style precludes its effective use in most situations.

[@@@ Photo 1, page 5]  Photo 1 (120 fps, shot at f/11, duration of .75 sec of the EG&G 553; printed on medium Kodabrome paper f/11, 10 sec).  The wink was initially touching the base of the pot (said to be nurdled).  From start to entering the pot, the shot took 1/2 sec.  Half a flip took 1/24 sec.  Notice that the wink bounced up some inside the pot, but it did not bounce out.  Also notice that the pot moved slightly.  This may be due to the hard backwards pull on the mat from the shot, or from my hand hitting it; probably the former.

[@@@] Photo 2 (120 fps, same as P#1).  Failed attempt to pot a nurdled wink.   Comparing with P#1, the first visible position of the wink off the mat is closer to the pot in P#2 (about 2.5 mm vs 5 mm) and it hit the back edge of the pot and car[r]omed off at about 3 feet/sec at a very slow flip rate.

Slide 2/6 (120 fps, same as above) 8 inch pot -- half flip in 1/40 sec, total shot 1/3 sec

Slide 3/2 (120 fps, same)  5 inch pot -- half flip in 1/30 sec, total shot 1/5 sec.

Slide 1/5 (60 fps, f/11, .75 duration) is like Photo 2, but after hitting the back rim, the wink ricocheted straight up without flipping.  Velocity upward near rim is about 3 feet/sec.

Slide 1/6 (60 fps, same) is fairly similar to Ph[o]to 2.

Slide 3/20 (120 fps) shows a nurdled pot attempt where the wink went straight up and down without hitting the pot.  Half flip took 1/30 sec.  Pot was moved by my hand.  The height of the wink from the mat reached about 11 to 11.5 inches.

Slide 3/27 (120 fps) shows an impressively successful pot of a totally nurdled wink (except the wink bounced out of the pot, but the flash had stopped before it did!).   The wink went up out of the frame, possibly as high as 13 to 14 inches from the mat.  Half flip time was 1/60 sec -- the fastest encountered.

2. Squopping.

Squopping is storking a wink with a squidger, aiming to have the wink land on top of another.  Nearly all players squop with the squidger angled down (80° to 50° angle) toward the target.

[@@@] Photo 3 (120 fps, f/11, .75 sec duration; printed at f/11, 10 sec) 1.5x enlargement.  Attempt to squop a wink an inch away.  Notice that the wink does not turn over, or bounce upon landing, although it achieves a 45° angle in the middle of the shot.  Shot lasts 1/8 sec.  A sharp squidger was used.

[@@@] Photo 4 (120 fps, same as Photo 3)  Attempt to squop a wink 3 inches away, with sharp-edged squidger.  Wink achieves a height of 2.1 inches, and flips over just once, sliding upon landing, which is optimum for success.  Shot lasts 1/5 sec = half flip time.

[@@@@] Photo 5 (120 fps, same as Photo 3)

Attempt to squop a wink 3 inches away with a round-edged squidger.  Similar to Photo 4, but lands shorter, with the leading edge of the wink hitting the mat first.   Ordinarly, this leading edge would butt the target wink., except, as in this case, the edge hits the target and does not bounce much.  Comparing this photo with Photo 4, it appears that a round-edged squidger will send a wink as high into the air as a sharp squidger, but for a shorter distance squop (about 3/4" shorter here).  This difference is probably one reason why sharp squidgers are clearly preferred by nearly all players.

[@@@] Photo 6 (120 fps, same as Photo 3)  A 3 inch squop attempt with sharp-edged squidger.  This photograph shows what happens when the force on a squidger does not give it enough height.  This is similar to Photos 4 & 5, but the wink hits the mat too soon, with about an 80° angle, and therefore bounces.  Shot lasted about 1/4 sec.

[@@@] Photo 7 (120 fps, same as Photo 3) Another missed 3 inch squop, using a round-edged squidger.  Like Photo 6, the wink hits the mat with its leading edge, this time almost perpendicular, and starts to roll, which is often disastrous in a game.

Slide 3/10 (120 fps, f/11, .75 sec duration) is a 5 inch squop attempt, similar to Photo 4.

Slide 3/8 (120 fps, same as Slide 3/10) is a 5 inch squop attempt.  It shows a shot error opposite to that in Photo 6.  The wink is sent too high by the squidger, turns over too early, and lands on an edge, and bounces around a bit, though not as much as in Photo 6.

Since the squop requires more precise placement of a wink that the pot shot, which has a 2 inch diameter target, bouncing upon landing increases the likelihood of missing the target.  Notice that in the 1 inch squop (Photo 3), the wink did not turn over, and that squops of greater distances turn over usually just once.  Since shorter squops require less force, they attain less height, and while they attain a sharp angle, they do not bounce on the leading edge upon landing.

[@@@] Photo 8 (120 fps, f/11, .75 sec duration; printed f/11, 20 sec) seems to provide a counterexample to the above theory for the motion of a wink in a squop attempt.   The wink maintains the same angle to the mat throughout.  While I cannot explain this motion with certainty, I expect that it is due to the shape of the wink.   Winks are not perfectly flat.  One side is slightly concave, the other slightly convex.  Winkers long ago discovered that shooting a wink which is concave down will give the wink less height than when concave up. Since by habit I usually place the wink concave up, it may be that this photo is of a concave down wink being shot, while all other photos are of concave up winks.  What it shows certainly agrees with experience in playing winks.

3. Bristol.

A Bristol is where two winks, one squopping the other, are sent toward a third wink to squop it..  It requires a particular setup where the top wink is not resting on the mat, but rather is held off the mat by the winks below it.  The squidger is held so that the diameter is in line with the direction of the shot, rather than perpendicular as in just about every other shot.  It is for this shot that a one inch squidger is popular.  I tried both a 1 inch squidger and the regular 1 3/8 inch one in my multiflash photography.

[@@@] Photo 9 (120 fps, f/11, .75 sec duration; printed f/11, 20 sec) In this Bristol shot, the top wink fails to maintain enough forward momentum, and falls over backwards off the wink it initially was on.  The result is a missed shot in most cases.   Magnification is 1.3x

[@@@] Photo 10 (120 fps, f/11, .75 sec duration; printed f/8, 35 sec)   Magnification 2.5x.  Notice how the top wink rears up and at one pointed is angled back away from the target (about 85° to the player), but momentum keeps it from falling over backward, and it falls back down on the wink it was originally squopping, which squops the target wink and produces a successful result.

Slide 3/32 (120 fps, f/11, .75 sec duration)  A successful Bristol from a different angle than Photo 10.

4. Boondock.

A boondock is a shot where the squidger forcefully slides between one wink and a wink squopped by it, sending the bottom wink far away from the scene.  (The official rules require that the top wink be at least grazed by the squidger first.)  The boondock is performed in a similar manner to the squop, except with as much force as possible (starting within a half inch). It is therefore the shot which sends winks at the highest velocities.

[@@@] Photo 11 (120 fps, f/11, .75 sec duration; printed f/8, 12 sec) The bottom wink is successfully boondocked by the top one, at a velocity of about 4 feet/sec.  Angle of boondock is about 40°.  Magnification 2.3x (see 8x10).

Slide 3/28 (120 fps, f/11, .75 sec duration) A more forceful boondock, with a velocity of 8.4 feet/sec and an angle of around 50°.

Conclusions

Stroboscopic photography offers an excellent means of investigating the motions of tiddlywinks shots, which last less than 1/2 second in most cases.   A photograph showing how a particular shot went wrong is just as useful as a photograph showing a successful shot.  Seeing where and when a wink hits the mat or pot, or flips, or at what angle it is at, is helpful in understanding the result of a shot.

There are a number of topics of study which I thought of during this project but did not investigate in great detail.  The thickness and compressibility of the playing surface, or the use of different material for the surface would be interesting to look into.  How the concavity and warps on a wink affect the shot was another idea I was interested in; also how the squidger's angle on a wink affects the rate of flipping.   All of these topics would best be investigated using a consistent machine to perform shots repetitively with unvarying force and direction.

Appendix

Correlation of Photo numbers herein with personal negative identification numbers:

Photo 1 = E21/23

Photo 2 = E21/16

Photo 3 = E24/8

Photo 4 = E24/14

Photo 5 = E24/18

Photo 6 = E24/16

Photo 7 = E24/17

Photo 8 = E22/28

Photo 9 = E24/25

Photo 10 = E24/22

Photo 11 = E22/4

Slide rolls 1 and 2 are Ektachrome 400

Slide roll 3 is Ektachrome 200

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