Hidden Hangersby BOB JEWETT

SOME SHOTS AREmuch easier thanthey first appear, ifyou can recognizehow a particularprinciple of physicscan be applied. Theexamples below eachdemonstrate somephysical principlethat you can use to

help you approach perfection, or at leasthelp you win some games you would havelost, if you learn how to recognize them.

Diagram 1 is a position from 9-ball, withonly grandstand shots available to pocketthe 7. Freeze the cue ball behind the 8 and9 for a safety, and the game is yours, but itlooks like the needed control is improbable.In fact, the shot is easy if you hit half the 7on the right side, half full.

The "half-ball" shot is the single mostimportant shot to understand for positionand safety play. It's defined as a shot inwhich the cue ball is rolling smoothly onthe cloth when it hits the object ball halffull. The resulting cut angle is 30 degrees.The important thing to remember is theangle the cue ball is deflected is nearly con-stant for a wide range of cut angles. This isa useful tool for cue-ball control.

In Diagram 1, the half-ball principle willtake care of the angles after the 7 is hit, soyou should concentrate on the speed. Anadditional aid from physics on this shot isthat the cue ball looses energy rapidly whenit hits the rails, so the two rail hits in thecorner "kill" the ball right behind the 8.

Suppose that the cue ball starts only twoinches from the head spot instead of a dia-mond. Now the shot is guaranteed toscratch unless you get just the right amountof stun to widen the angle, and that's toughat long range. The half-ball angle can bechanged a little with side. Try outsideEnglish (in this case right English) to see ifyou can widen the angle when the cue ballrolls away from the 7.

The half-ball angle can also be used forsome amazing offensive plays. The shots inDiagrams 2 and 3 are to make the 1 ballfrom the two cue-ball positions. In Dia-gram 2, if the 1 hits the right side of the 2ball, it easily goes in the corner pocket. Becareful to play the shot just a little fasterthan you may think necessary to get the 1 tothe pocket. Be careful; if the 1 ball is slid-

20 Billiards Digest • February 1997

ing, rather than rolling, when it hits the 2, itwill take a wider, unpredictable angle.

For Diagram 3, the 1 goes in off eitherside of the spotted 3 ball. On this shot, it'sa little harder to get the ball rolling smooth-ly before the collision, so favor a somewhatthinner hit than half-ball on the 1-3 hit.Shots like this come up frequently oncrowded straight-pool, one-pocket and 8-ball tables. Learn the angles by heart.

To really get a feel for half-ball shots, tryEnglish billiards, a three-ball game playedon a snooker table. Half-ball shots are anintegral part of making caroms, which isone of the ways to score in that game.

Diagram 4 is an all-too-familiar scenefrom straight pool. It's not a bad break shot,except for the very thin cut angle. A mucheasier shot is the short carom, playing thecue ball off the corner ball to the one.

What makes this shot easy is that the cueball travels a very short distance on thecarom. In fact, if the distance is less than aball's width, the carom is easier than astraight — in shot of the same length. Beforeyou try this, check the "ideal line," whichtouches the edges of the two object balls. Ifthat goes to the pocket, the shot haspromise. The "feel" of the shot is like

scratching off the first ball with a stop shot.This shot needs practice, both to get the

aiming down for shots that aren't sitting so

perfectly, and to learn how side spin can fixthe angle if it's a little off. Get something toset the balls in the same place each time, soyou can repeat a shot exactly. I like self-adhesive paper reinforcements used to pro-tect the punch holes in binder paper. Awarning about playing the cue ball off amiddle ball in the rack: if the rack is tight,the cue ball will carom at a wider angleunless the hit on the first ball is thin.

Everyone likes to shoot stop-shot posi-tion; there are few things more satisfyingthan smacking the object ball full in theface and stopping the cue ball absolutelydead. It turns out that the shot is easier thanit looks, and is far easier than getting thecue ball to drift forward or back a diamond.The "trick" to stop shots is to collide whenthere is no draw or follow on the cue ball.The problem is that you need to start withsome draw for the cloth to rub off on theway to the object, ball, and you may arrivewith a little spin; one way or the other.

In Figure 5, a perfect shot is shown byzero ball movement for zero units of drawor follow on the cue ball at the instant ofcontact. If one "unit" of follow is on the cueball, it will roll forward a ball diameter, andexactly replace the object ball. (How many

22 Billiards Digest • February 1997

RPMs are in a "unit" depends on details wewon't discuss.) Thus, an error of one unit ofspin when trying a stop shot means the cueball will be off by only 2.25 inches.

In comparison, suppose you want to pullthe cue ball back 20 inches or nine balldiameters. This takes three units of draw. Ifyou are off by one, the cue ball is either fiveballs short of position or seven balls past.

How is this useful in play? It means thatprecise stop shots are easy to learn andplay, but moving the cue ball exactly a dia-mond will be much harder and frustrating.The result also applies to stun shots — stopshots at an angle — which are easier tocontrol than "half follow" or "half draw"shots.

A final physics gem is in Figure 6. Itanswers the question "At what heightshould a shot be cued for maximum accu-racy of travel distance?" The lag shot to seewho breaks is a simple example. The curvesupposes that the cue speed is constant, butthe bridge height varies (perhaps randomly)giving varying amounts of draw or follow.While any height can get the job done —for draw, just shoot twice as hard as forcenter ball — the point with least effort isabout half way between center ball and amiscue.

Notice that if you're a little away fromthat best tip height, there is very littlechange in distance travelled, while if youstart farther away, you must be more andmore accurate on the height to achieve thesame distance accuracy. What might causeyou to hit at the wrong height? Does yourelbow drop?

When you see one of the shots above, getNewton on your side and shoot it the easyway.Bob Jewett is a former ACU-I pool champion andcurrently trains BCA instructors in San Francisco.

24 Billiards Digest • February 1997

Finding The Pocketby BOB JEWETT

IRVING CRANEHAS said that theskill that set himapart from other topplayers was his pock-eting accuracy —putting the ball rightin the center of thepocket. When wasthe last time youworked on this part

of your game, and just how do you practicethis? Below are some suggestions for get-ting your shots closer to the real target.

First we need to know where the pocketis. Obvious? Maybe not. Lots of players,and not just beginners, have trouble playingshots angled into the side pocket. The ten-dency is to set the target too close to theback of the pocket, so the object ball hitsthe cushion at the near corner of the pock-et. As the angle of approach to the side getsmore difficult, selecting the right target ismore and more important. Where is the besttarget?

Let's first assume that there is a "singlebest target" for all angles of approach. Ourgoal is to mark that point to make practiceeasier, and to know that point to use duringnormal play. This point must be on the cen-terline of the pocket as shown in Diagram1, as long as the pocket is symmetrical —the same on each side. Where on this line isthe single point?

Consider the toughest possible angle intothe side. At the limit, the object ball willbarely miss the near corner of the pocket,and pass exactly through the phantom ball.Note the point on the short rail that the cuestick passes over. The point on the short railand the center of the phantom ball give aline that goes through the center line. The"single best target" for the side pocket isthat point on both the center and extremelines.

Where this extreme line is will depend alittle on how the pocket is made, but onmost tables, a ball can be made from thecenters of the short rails. On my table, thisline crosses the center line exactly at thebrink of the pocket where the slate starts tofall away. Try on your own table to find thelimit using short, straight — in shots.

While the point we've found is clearly thebest target for the two shots analyzed, is itthe best target for all shots to the side? Trysome experimenting to see if it is the best

30 Billiards Digest • April 1997

target for shots between the center and theextreme lines.

Where is the "single best target" for thecorner pockets? Since corner pockets arealso symmetrical — the short-rail side ismade just like the long-rail side — the tar-get must be on the pocket's center line,which is the 45-degree line in Diagram 2.

Once again, consider the extreme case,which now is when a ball is coming rightdown the rail. Notice the rail groove — theline worn in the cloth where a ball sitswhen it is frozen to the rail. One easy wayto find the target in the corner pocket is tofreeze several balls together in a line oneach rail by the corner — they are all sittingin the rail groove — and place a ball in thejaws of the pocket in line with the two linesof balls. The base of the ball gives the "sin-gle best target" point.

Again, you may want to try approachangles between the two angles to seewhether the single point is really a goodtarget for all shots.

Now let's apply the theory to practice.Get some self-adhesive donut-shaped whitepaper reinforcements. (The kind used onpages in a three-ring binder; they come inrolls of a hundred.) Place them on yourpractice table, one donut at each pocket'starget point. If you can't find donuts, whitechalk will also work, but tends to wear offduring the course of a practice session.

As you go through your normal practiceroutine, strive on each shot to drive eachobject ball exactly over the target point. Besure to note on each shot how much erroryou made to one side or the other. Over theedge of the donut is good, but try to roll theobject ball directly over the center.

While using this practice aid you mayfind out, like I did, that on some shots thepocket isn't where it appears to be.

The rail groove is also the "reflectingline" that mirror banking systems dependon. If a ball starts slightly off the rail and isshot slightly into the rail, it will be reflect-ed from this line. That means that if youcould see the image of the pocket reflectedin a mirror on the line, it would be thepocket for shots aimed a little too far intothe rail. The important thing for us is thaithis "image" pocket (shown in gray inDiagram 3) provides another pocket, justlike the real pocket, but for balls reflectedoff the cushion. The center of the combina-tion of these two pockets is on the railgroove. This gives us our second line tofind the "single best target" for the cornerpocket. Note that it is also the intersectionof the straight extension of the two railgrooves.Bob Jewett is a BCA billiards instructor and aformer ACU-1 national college pool champion.

Collective WisdomIt seems they've heard all the questions, but the pool

players on the Internet still have no consensus about cues.

DO YOU LIKE tohang around the poolhall and discussimportant topics overa beer or a cup ofcoffee? Subjects likewhat kind of cloth isbest, Efren Reyes'latest miracle shot,whether inside Eng-lish makes the ball

hug the rail, where the best action is inL.A.... When a pool hall isn't handy, youcan get your pool-chat fix in the Internetnewsgroup rec.sport.billiard (r.s.b forshort). If you happen to find yourself incyberspace, drop on by.

There is a standard practice in news-groups called a FAQ list, for "FrequentlyAsked Questions." Once online for a fewmonths, you'll find that each crop of new-comers tends to ask the same questions. A

by BOB JEWETT

list of those questions with answers is com-plied by many volunteers to avoid some ofthe repetition. It helps the newcomers getup to speed without boring the old hands,having to answer the same question againand again. The FAQ is updated as newcom-ers bring up questions that haven't beenasked before.

Some of the answers on r.s.b.'s FAQ arejust pointers to other resources on the Inter-net, such as the BCA's web page that hasthe rules for the major pool games, or theE.J. Riley page that has not only snookerinfo, but covers other cue sports as well.Mark Avion, an r.s.b regular, has assembledand maintains a list of over 300 online linksto pool, billiard, and snooker pages.Another, Ira Lee, has illustrated instructionof three-cushion — within a couple ofclicks you'll see how to avoid that peskyfive-cushion kiss-out you always get.

The two most common sorts of questions

are about rules and cues. The FAQ brieflylists rules for 11 games, and suggests thepurchase of a real, physical, paper rulebook. I'll go into cue selection fartherbelow, but first let's look at some of theother questions (with abbreviated answers)from the FAQ.

Q: How can I make my own table andcue?

The intrepid handyman is directed to arti-cles in Fine Woodworking Magazine forplans, the July/August '86 for the cue,March/April '89 for the table. (Call 1-800-477-8727 for info). An r.s.b contributor,Bob Stantley, has a story online of how hebuilt his own table between Memorial Dayand Labor Day.

Q: How can I learn about pool physics?Besides the books by Jack Koehler and

Wayland Marlow, there is a 60-page mini-

24 Billiards Digest • June 1997

dissertation available online by r.s.b'er RonShepard with discussion, equations, anddiagrams covering many aspects of sticks,balls, and cloth. Also, two books in Frenchare available: a reprint of Gustave Coriolis'1835 master work, and a recent book byRegis Petit.

Q: How much room do I need for atable?

I'm amazed by how many people want tojam a pool table into a 12-foot by 15-footroom. Briefly: leave at least 64 unob-structed inches around all sides, or beready to shoot with a cut-down cue. Tofind your personal elbow room needs,place a piece of plywood near a pooltable like a wall, and move it back untilyou are comfortable shooting near it. Youmay want chairs and such in the room aswell, so be sure to leave room for them.

Q: What is the "Diamond System?"It is hard to describe any of the many

diamond systems FAQ since it lacks tablediagrams, but an example of the corner-five system is illustrated using text char-acters to draw the table. The reader isthen directed to books by Robert Byrne,Eddie Robin and Walt Harris.

Q: My shaft has a dent. What now?Eight different methods are discussed

in a page and a half, ranging from justrubbing with a glass rod to steaming witha wet cloth and a soldering iron. Try astream of steam from a tea kettle directedthrough a small hole punched in alu-minum foil. Disclaimer: neither BilliardsDigest nor I will replace your shaft if youruin it.

And finally...

Q: What kind of cue should I get?If opinions were pennies, r.s.b would be

rich beyond compare. Someone mightmention that his Williams Swash-bucklerhits the ball great, and the next person willcall him an idiot for owning such crap.When you get into personal things — reli-gion, sex or cue sticks — on the Internet, beprepared for "strong interactions," as thephysicists say.

Before buying a stick, you might askwhether you're ready to own one. There isa huge variation between sticks availabletoday, and if you're a relative beginner,your game and style may still be evolving.Trying different house cues will let youfind a type that fits you now. When yourstyle has settled down some, and your game— especially the spin part — has developed

to the point that the stick becomes impor-tant, buy your first stick.

Here's a quick test to see if you'll benefitfrom cue ownership. In Figure 1, Shot 1,shoot the cue ball straight up the middle ofthe table with side spin. Can you consis-tently hit the side rails beyond the sidepockets? In Shot 2, can you consistentlybring the cue ball clear across the table withjust draw? If so, it's time to buy a stick,carefully.

Q: Which brand?It is pointless to suggest a particular

brand, since sticks within a single brandoften hit the ball very differently.

You need to play with a cue for a while tosee if it is right for you. If purchasing at aretail store, ask to shoot with a variety ofsticks, and include the test below. If thestore refuses to let you chalk the tip — acommon problem reported in r.s.b — goelsewhere. If you buy by mail order, askabout the return policy. The stick must beable to spin the ball properly.

Some basic properties of the stick areobvious — diameter, length, weight, bal-ance — all of which you should sort outduring your "house cue" phase. In a jointedcue, you also need to select the joint, wrap

and decoration.

Q: What about joints, wrap and decora-tions?

There are lots of opinions about joints.The problems, like the cues themselves, isthat there seems to be nothing but opinions,so the FAQ isn't much help when it comesto joints. For the wrap, get something thatdoesn't let your hand slip even on hardshots, unless you feel the bizarre urge to

develop a slip stroke. For decoration,realize that you're buying style ratherthan playability.

Suppose you have a stick in hand,ready to test. What shots should you try?First, just shoot straight over the spots,like Shot 1 but without spin, at variousspeeds. Is the stick solid or does it havea click, rattle or buzz? You should onlyhear the quick thud of tip on ball. Next,try the shots in Figure 1 to see if the sticklets you spin the ball up to your usualstandard.

The last test is a little more complicat-ed. It measures the single most impor-tant characteristic of a stick: how muchit makes the cue ball veer to the sidewhen applying side spin. This is knownas "squirt" or "deflection."

As shown in Figure 2, place the cueball about 12 inches from an object ball(no pocket is involved). Line up as if fora perfectly straight shot right through thecenter of the cue ball full at the objectball. Now, without moving your bridgehand, pivot the stick for a maximum leftspin shot without draw or follow. Strokeand shoot along this new line. Squirt willmake the cue ball go to the right of theexpected line, and for a very squirtystick it may even hit on the right side ofthe object ball.

Now for the hard part. Adjust your bridgelength so that the cue ball lands full on theobject ball, and sits there spinning in placeif you don't draw or follow. If the cue ballmoves to the left, lengthen your bridge; tothe right, shorten.

The distance between the cue ball and thisperfect pivot point measures the squirtquality of the stick — lengths betweeneight inches and three feet have beenreported in r.s.b — and longer is better.

This method of measuring squirt can alsobe used to compensate for it during aiming,provided that you adjust your bridge lengthto the perfect pivot point. Aim without sidespin, and then pivot the cue over to give asmuch spin as you need and stroke through.Bob Jewett is the keeper of the rec.sport.billiardFAQ (http://www.accessone.com/~mavlon/faq.txt).

26 Billiards Digest • June 1997

Those Who Can, TeachBasic techniques to instruct those who need it, without getting too technical.

by BOB JEWETT

IF YOU HAVEplayed seriously formore than a fewmonths, you'veprobably alreadydone a fair amountof instructing. Ifyou find it fun tohelp others playbetter, thiscolumn has

some tips that will improve yourinstruction. On the other hand, ifyour game is not up to the levelthat you want to share it with oth-ers, just adopt the role of the stu-dent as you read the following.

Do you know a player who is allslam and no finesse? The drill inDiagram 1 may help him tonedown his "enthusiasm". It comescourtesy of Ed Nagel, a long-timeinstructor on the West coast.Starting from the position shown,the goal is to make the object ballin the side pocket, but it must takeat least four soft strokes. Theobject ball must be driven towardsbut not to the far pocket on each ofthe first three strokes. This can beturned into a competition to seewho can take the most shots tosink the ball; can you stretch it outto thirty? Many players are slow todevelop the "soft" part of theirgame; this lack is usually mostevident when they try to play softsafety shots.

The shot in Diagram 2 has giventremendous pleasure to manybeginners, believe it or not. Theidea is to get even the clumsiesttyro to draw the cue ball, a delight-ful result that all too many playershave never experienced.

Although the diagram appearssimple, there are lots of details thatyou as the instructor need to takecare of to make sure the shot

comes off correctly. The position is veryimportant, with the object ball one dia-mond straight out from the pocket andthe cue ball on the center line of the tablebut just off line from straight in. The shotis easy, the aiming is obvious, and theslight angle keeps the cue ball from spin-ning directly back at the shooter, so hecan stay down. Note also that the stick

will not pass over the rail at the pocket,so a high pocket liner can not prevent alevel stick.

The bridge is absolutely critical on thisshot: a fist bridge with all of the endknuckles of the fingers planted firmly onthe cloth. A fist bridge is formed by mak-ing a fist, and then looping out the indexfinger barely enough to get the stick

• \ t I \

through the loop. The thumb should hold the tip of the indexfinger against the middle finger. Do not let the student uncurlthe middle finger — its tip must remain touching the palm ofthe hand. The shaft should be off the cloth by exactly the diam-eter of the thumb. Most beginners can make a reasonable fistbridge even when the standard fanned-finger closed bridge isimpossible for them.

Chalk! Do not trust the student to do this correctly; inspecttheir work. Stand in front of the target pocket so you can see thepart of the tip that will hit the ball. Also, you can act as short-stop if there's a major miscue.

Once the student is down in position, have him adjust thelength from bridge hand to ball to get a reasonably low hit, butnot a miscue.

Now that the position is set, tell the student that you want tosee nothing move except the stroking forearm until the cue ballstops moving. Remember to be in position for your short stopduty.

Most will draw the cue ball back to the side rail on the first

try. For those who don't, the most common problem is raisingthe bridge hand just as stick comes forward, probably due tofear of miscuing. In this case, set up the shot again, and say justbefore the shot, "Put a little pressure down on your bridge hand.I want to see all those knuckles touching the cloth."

If a lack of speed has prevented that soul-satisfying zippy draw,say just before the shot, "Shoot firmly." Do you agree now thatthere is a lot more to this shot than meets the eye? Once you getthe details down, in just a couple of minutes you can get yourstudent to draw like never before. Along the way you havetaught a firm, closed bridge, minimization of body movement,the importance of chalk (is your stomach sore?) and the factthat amazing draw can be imparted without much effort.

In my column last time, I described a way to measure one ofthe three pitfalls of side spin — squirt. The next two diagramsdescribe how to demonstrate the other two — curve and throw.

Diagram 3 is a curve shot beginners can make with just aminute or two of instruction. The idea is to get them to do theshot themselves, rather than for you to demonstrate it. In theposition shown, making the ball by the pocket is clearly impos-sible, since if the cue ball misses the near ball it must also missthe far ball. Point this out, and then tell the student, "Just useright English, and make your normal bridge up on the rail. Aimto just miss the first ball." The automatic elevation from beingup on the rail guarantees curve if they can manage any signifi-cant side spin. You may need to suggest a little draw with theside spin to increase the effect, and a soft hit works better than

a hard one. Chalk! Most beginnerscan get too much curve after a cou-ple of tries.

Diagram 4 illustrates twoaspects of throw. In 4A, the objectball, if struck straight on, willclearly miss the pocket. Have thestudent play straight at the ball, butwith a little left side spin. Exceptwith the cleanest new balls, theshot goes right in.

Diagram 4B illustrates an amaz-ing shot. Again, even people whohave never before picked up a stickcan do it themselves. The point isto stress the importance of cleanequipment. Spot a ball, and freezethe cue ball to it. Prior to placingthe balls, chalk the contact point. Aquick way to do this is to breatheonto the ball for condensation, rub youryour finger down in the depression in achalk cue, and then roll your chalky fin-ger print onto the ball, forming a thinlayer of chalk mud.

Have the student pick a far corner pock-et, and then tell him to shoot with the

stick pointed directly at the pocket and touse outside (left for pocket B) English.

If you would like to perfect your teach-ing technique, the BCA offers severallevels of courses. If you have little teach-ing experience, I'd recommend the one-day course to become a Recognized

House Instructor. If you have extensiveexperience already, the three-day Certi-fied Instructor course at one of the six orseven Master Academies may be right foryou. Contact Bruce Baker of the BCA at319-351-2112, or see the BCA Web pageat http://www.bca-pool.com/.

A SAFETY DANCEWhen a delicate touch is required to hook your opponent, explore the options.

by BOB JEWETT

IT WAS MY ownfault, really.

I had left myself onthe last ball — it hap-pened to be a nineball game — as inDiagram 1. There•was no good safetyoff either side of theball, and no bankshot was available.

My choice was to play a soft shot directlytowards the ball, leaving the same positionbut with even less space between the ballsand the object ball nearly frozen to the rail.My opponent was unlikely to have the del-icacy of touch to play a safety without dou-ble-hitting the cue ball, or so I smuglythought as I left the table.

His surprising play was to lay his stick onthe table as in position A, with the tipslightly under the edge of the cue ball.With one hand, he lifted the shaft end of thecue straight up to position B in Diagram 2,hitting the cue ball a light, glancing blowthat was just hard enough to get the objectball to the rail and leave everything eventighter. This shot, which I had never seenbefore, brings up a question: Can he dothat?

Before we start on an answer, let's look atsome other ways to play the shot.

B. The Drop. Hold the stick by the ferrulein position B and drop it. Be careful not totake too much cue ball or it may roll backfor a foul.

C. The Waggle. This is the same idea butsideways. With a normal bridge in positionC, slowly bring the stick forward and to oneside of the cue ball. Now move your griphand not forward but sideways, keepingyour bridge hand locked tightly on the shaftto prevent and forward/backward motion.

D. The Hara-kiri. This method wasshown to me by two different players.Stand right by and facing the object ball.Hold the shaft in the fingers of both handsand jab the cue ball lightly. A little practiceyields surprisingly good control.

E. The Dead Masse. Using an elevation

of at least 45degrees, shootsoftly right at thecenter of the cueball. Bridgingsolidly for thisshot may requireingenuity andcontortions. Theprinciple of theshot is thatshooting downinto the tabletakes a lot ofenergy awayfrom the cueball. The greaterthe elevation, theless speed thecue ball will

have. Using a dart-throwing grip for theback hand gives better control than a stan-dard grip. I feel this technique gives thebest control, but needs a little more practicethan some of the others. It is useful for arange of situations whereas the first fourwork only for the single, rare situation.

Which of these techniques is legal?Under current rules, they all are. ForMethods A, B, and D, the player shouldnote that it is a foul to lay the stick on thetable and release it while lining up a shot.

Which of these techniques should belegal? Should the player be required to

hold the stick when it hits the ball (B)?Should a hand on the back half of the stickbe required (A,B,D)? Should a generallyforward motion of the stick be required(A.B.C)?

Please send me your opinions on this shotin care of this magazine or by email to: Jew-ett @netcom.com, and I'll summarize thefeedback in a future column.

Bob Jewett is now the Secretary of theUSBA (carom association) and is anInstructor in the San Francisco BilliardAcademy.

20 Billiards Digest • October 1997

Welcome to Masse 101Tips for mastering one of the game's most difficult shots.

by BOB JEWETT

I'VE LIKED MAS-SE shots ever sinceWillie Mosconi toldme to shoot them.

It wasn't in person,but his WinningPocket Billiards, thebook that first taughtme how to play, hastwo masses amongthe fancy shots at the

end. To be able to amuse and amaze onlook-ers is enough reason to study the shots, butthere is a practical side to masses. If youknow how to play them, you'll be ready forthose not-so-rare situations in games when amasse is the right shot to play.

First the theory. In his 1835 book, whichhas recently been reprinted, the Frenchengineer Gustave-Gaspard de Coriolisdescribed the aiming system shown inFigure 1. The good news is that the systemis accurate as far as it goes: the bad news isthat the shot is still largely by feel. The sys-tem tells you which direction the cue ballwill take after it stops curving. What it does-n't tell you is how long the curve will take;you control that by the speed of the hit.

In the side and top views,note the two points on thecloth. The point where thecue ball is resting is obvious.Harder to visualize is thepoint on the cloth that thestick points to, which we'llcall the "aiming point."Coriolis' truly remarkableresult is that the final path ofthe cue ball will be parallel tothe line joining these twopoints. This is shown in thefinal part of the figure wherethe cue ball starts out parallelto the line of the stick andgoes immediately into acurve, perhaps 45 degrees ofpath change, which requiresabout 45 degrees of elevation.

Suppose you want the cueball to take a full right turn —90 degrees — after thecurved part of the path. Forthis you have to adjust theelevation and perhaps addsome draw so that the stickpoints on the cloth to an aim-

ing point just tothe right of theresting point asseen from yourside of the cueball. This visual-ization is hard because your eyecannot look directly along theaxis of the stick, so there is someguess-work about where exactlyit points. Also, the aiming pointis not very far from the restingpoint, so accuracy is hard.

Note that if you want the cueball to go out and then backtowards you. the aiming pointmust be under the nearer side ofthe cue ball, so the line from theresting point to the aiming pointalso comes back toward you.

What is the shape of thecurve? It is always a parabola.

Reports of cue balls going in "circles" aremistaken, and figure-eights are impossible.Some typical parabolas — in case youwiped them from your mind as soon as youescaped from algebra — are shown inFigure 2. In theory, any section of any ofthese curves, expanded or shrunk, is a pos-sible path for your cue ball.

Some parabolic paths that solve a singleshot are shown in Figure 3 (p.34). In eachcase, the line of the cue stick sets the initialdirection of the cue ball and the arrow headmarks the end of the curved portion of thepath. Can you find a stick alignment and anaiming point for each of the three

continued on page 34

32 Billiards Digest • December 1997

T E C T A L K

shots? Can you imagine about how muchelevation is required for each?

While Coriolis will help you get the direc-tion right, the extent of the curve — how farthe ball goes out before it breaks — needs afeel for the speed of the shot. That requirespractice, and useful practice requires goodfundamentals. You must approach each shotmethodically and execute it with as muchmechanical stability and accuracy as you

can muster.A firm, raised open bridge is essential. If

you practice the shot in Figure 3. the railprovides additional height. This shot doesnot need the "flying bridge" you might seetrick shot artists use. with the hand entirelyoff the table. Find the minimum elevationand speed needed to make the shot; that'salso the highest-percentage way.

If you do need a longer bridge for more

power with the cue ball near the rail, sitpartly on the rail so you can form a normalclosed bridge on your thigh. If the cue ballis a diamond from the rail, try placing yourleft knee out there as a bridge platform. Becreative and flexible, but above all, bestable.

There are two common grips to use. Forrelatively soft shots — nearly all practicalshots in game situations — the dart or pengrip gives best control. Extreme powercomes more easily with the normal grip. Ineither case, your forearm should still be per-pendicular to the cue stick even thougheverything is up in the air.

Next time I'll go over more equipmentproblems and some practical uses of massein game situations. Until then, work on thefollowing practice: With the balls set up asin Figure 3, try to pocket the duck with theabsolute minimum of speed needed. Ideally,the cue ball will not have enough energy toget to a rail after pocketing the ball. Also.keep the elevation down to make aimingeasier. Once you are comfortable with theshot as shown, move the cue ball and theblocker back a diamond at a time. As youprogress up the table, remember, keep thespeed down!

For a little fun. try the shot in Figure 4.This position appears three times in themovie The Hustler, but the path shown ishow Allen Hopkins likes to shoot it: mini-mum speed to make the shot.

Note: If you plan to practice these shotson somebody else's cloth, ask first.Bob Jewett is the USBA secretary and an instruc-tor in the San Francisco Billiard Academy. Hecan be reached cit jewetl@billi(irdsdigestxoiii.

34 Billiards Digest • December 1997