Extreme effects of nap

rekoons wrote:

***There is a completely different (and mind boggling) reason why this only happens going toward the Baulk corners but we should save that for some other discussion. For now, post again and let me know if you have seen this version of the slide effect and if you are interested, we can discuss why it only works toward Baulk end (or let me know if you have seen the same thing toward Black end).

Ace, I think you still owe us an explanation on this...

Hi again, Rekoons.

As this is far removed from the original thread topic, I will start a new thread for it. The origination of this thread started here:

viewtopic.php?f=80&t=7150&p=589577#p588003

So as to the cause of this type of unusual fluke, Rekoons, you postulated:

As for why this should only occur in the baulk direction, and not the other way is beyond me. All I can think of is perhaps the run of the cloth?

And in fact, that is exactly correct as to WHY it happens only the one direction, but it does not explain at all WHAT it is that actually happens. So I will attempt to explain the science of what actually happens then in this post.

WARNING! This post is intended for players only. It will be long, and technical, and very probably quite boring. So don't bother to read unless you are thrilled by the mundane. Even so, I still expect to see a TL;DR. You have been warned.


I took a little while and found a pretty good example of this type of fluke here:

https://www.youtube.com/watch?v=l9_HngD ... u.be&t=142

It is not quite the same because the first Red plants onto the second Red, but very often, the same thing happens where the very first Red simply drops into the (in this case, Green) corner pocket. I will describe the science of it as demonstrated in this particular video....i.e., the Red is played from near Pink spot into the Green side middle pocket and ultimately flukes into the Green corner pocket. I have witnessed this at least a dozen times on my own table, but always the fluke is into the Green or Yellow pockets; I have never seen the mirror image of the ball fluking into one of the Black pockets in a similar way.

First, we have to talk about a proper Snooker cloth. Here in the US sadly, many snooker tables are covered with the same cloth which is used on Pool tables. These play very differently than proper Snooker tables with Snooker cloth installed. Pool cloth is cotton based (I think) and very thin and smooth and it plays very fast with no nap. "Nap" refers to the directional aspect of Snooker cloth. If you brush your hand on it from the Brown spot to the Blue spot, it feels very smooth. If you brush your hand from Pink spot to Blue spot, you will feel the resistance of small fibers in the cloth. Snooker cloth is made from worsted wool. Now, I am not a clothier, but suffice to say that worsted wool is made from very fine sheep hair that is combed to lay all in the same direction. That is why you can actually feel the fibers of the nap when you brush your hand across it...it is made that way on purpose. Cotton cloths of Pool tables have no nap....therefore, balls roll in a straighter line. Snooker cloths are thicker with a fine to heavy nap (depending on the grade of cloth) so the balls will "roll off" some as a result. This may be due to the table being out of level, but even if the table is perfectly level, balls will roll off at slow speeds due to the thick, napped cloth. Imagine watching a golf tournament on telly and the camera zooms in on the golf ball rolling along the green....it is not a smooth movement as the ball hits bumps and grass blades. This is basically the same thing happening to a snooker ball on a snooker table. Of course, snooker balls are heavier than golf balls, and cloth fiber is finer than grass blades, but the effect is similar in principle if different in degree.

The nap of the cloth on a snooker table always runs from Baulk to Black. (At least it should....I have heard stories about people who did not understand this and then installed their own cloth incorrectly, either backwards or upside down.) So the way a snooker ball travels on the napped cloth will be affected by whether it travels WITH the nap, AGAINST the nap, ACROSS the nap, or most likely, a combination of these directions. The effect of this "nap roll" is small, but it is important and noticeable most especially when balls are traveling very slow speeds. And if a ball is spinning rather than simply sliding or rolling, there are even more complicated effects that occur.

So this effect is very subtle and usually ignored by players, but often, players are not even aware that the effect exists. I bought an instructional book written by Cliff "The Grinder" Thorborn nearly forty years ago. In it, he explains that he had been playing Snooker for ten years before someone he respected finally convinced him that nap roll exists and it is important enough to pay attention to and after understanding the effect, Cliff became a much better player. So you can play just fine if you don't know this or if you don't believe this. But if you accept these principles as true, you will become a better player, especially for strokes that require soft speeds and spins.
_______________________

Unless you already know this effect, then what I am about to write below, you will not believe. Put simply, you will NOT believe it. I can only hope that you will be interested enough to take a small amount of time yourself to try this at your own club so that you will actually see it with your own eyes. And after you do that the first time, you probably STILL will not believe it. So do it two, three, four times, whatever it takes, and finally, you will have no choice but to believe that what I say below is true. Don't take my word for it. You won't.

Let's start with a very simple, common exercise to test how straight you cue the White ball. Nearly everyone has done this before. Place White on the Brown spot. Try to hit the White perfectly center ball so that it travels perfectly straight over Blue, Pink, Black spots, off Black cushion, and comes back in a straight line over spots again to strike your cue tip center ball. That is perfect cueing and it is difficult to do for most players especially if you strike White with some speed.

But now, instead of White traveling back to your cue tip, strike it with pace so that is just comes off Black cushion and stops somewhere around Black spot. THAT is the speed I want you to remember. Do this a few times if you have to to memorize that exact speed, always just plain center ball. When comfortable with that, now you will put LEFT side on your White ball and play exactly the same shot. A reasonable amount of side, maybe one cue tip to the left of center. I am sure you know what will happen. White will start maybe to the RIGHT just a touch but it will arc to the left to travel over Blue spot and it will continue to drift left of the Pink and Black spots. If any spin remains in the White when it strikes cushion, you will see it kick off to the left side quite a bit, but it is possible that all of the spin has faded away at the slow speed.

You probably already know all of that but you should do it anyway. Next, you will do exactly the same thing but in the other direction. Set the White on the Pink spot and first play center ball and learn the speed to make White bounce off Baulk cushion just about a foot or less, as if there is a "phantom" Black spot there. When comfortable with that, now apply the LEFT side to White exactly like when you ran the other direction.

What will happen? Most likely, if you are like pretty much everyone, you think it will just be the same thing, only going the opposite direction. That is absolutely not correct.

Because of the nap of the cloth, a very strange (you might say mind-boggling) effect occurs. When you play the stroke with the LEFT side, again White will jump to the right initially like the other way, but then it will straighten out and it will not cross Blue spot. In fact, even though you put GENTLE LEFT side spin on it, the White WILL NOT come back to the left in an arc at all. It will begin to drift toward the RIGHT! When played at speed to just bounce off the Baulk cushion a foot, LEFT side spin will cause the White to drift to the RIGHT by about two inches (50 mm) by the time White strikes the cushion. If there is still any side spin remaining, it will still kick back toward the left a little bit just like normal.

I think that nearly everyone has seen this happen before. But when a player witnesses a roll off of this type, I believe the usual reaction is "Table isn't level" so nothing is learned from the observation. That is why you , the reader, must do this exercise yourself in order to believe that it is true. When you have this knowledge, it can lead to some very strange seeming shot choices. For instance, let's say you just want to roll the White ball from the jaws of the Yellow pocket, over the Blue spot, to finish just at the opposite Black corner pocket. Dead weight speed to just touch a ball sitting there. In that case, you just cue it straight and try to get the speed correct. But now reverse it.....White is in the Black corner jaws and now you need to roll over the Blue spot dead weight to the Yellow corner. If you just hit center ball, due to the nap of the cloth, White will roll over Blue spot (or maybe just a touch to the left of it) but as the White slows down, it will drift further and further to the left as it slows. It will probably strike the cushion 4 to 6 inches toward the middle pocket if you were aiming for center of the Yellow pocket. Maybe more with heavier nap.

So what do you do if you must play that White in a straight line at a slow speed against the nap as in this corner-to-opposite-corner stroke? You have two choices. You can either try to compensate.....aim well to the RIGHT of the Yellow pocket and try to judge how far the cue ball is going to drift to the left as it goes against the nap. This is EXTREMELY difficult to do. The exact speed the White is traveling has a major effect on when and how far the cue ball will arc as it slows down so put simply, it is extremely difficult to judge correctly. The second option, BELIEVE IT OR NOT, is to put that little touch of side on White ball.....BUT you will put side on White OPPOSITE of what your intuition tells you. To be specific for this example....you know that the White is going to drift off to the left when you strike center ball. So playing at an angle against the nap, to stop this drift to the left, you must put LEFT side on the White ball! CRAZY! And actually, it is far easier to judge this shot than the first option because, after all, you are simply lining it up in a straight line where you need to hit it. Having the counter-intuitive knowledge to put OPPOSITE side on the White ball turns this into to quite an easy shot to judge.

You cannot possibly believe this until you do it yourself. But remember, this effect ONLY acts this way when the White (or any other ball) is traveling quite slowly and traveling against the nap (straight against or at an angle against the nap). If you are snookered and you have to play a strong swerve shot against the nap, White will act pretty normally and if you strike White strong left with elevated cue, the White will swerve left like you would expect. It is just when White is slowing down and coming to a stop that it will act funny and you might actually notice a sort of "S" shaped arc if it comes to a stop before hitting a cushion.

That is a lot of information. And I have not even gotten to the bit yet about how the Red ball hugs that side cushion in the video. If everything that is written above makes sense to you, then you may be able to figure out yourself why that Red hugs cushion. This has all laid a good foundation. I have to take a break and walk the dog, eat dinner, etc. so I will try to get back to this tomorrow to finish up about the Red hugging the cushion.

Seems untrue but I trust you so will try it tomorrow.

Some people never wake up from them

Then I guess the red hugs the cushion toward the green corner pocket, because after it hits the near jaw of the green side middle pocket (as seen from the pink spot) right hand side is automatically put on the white, and because of it running against the run of the nap this right hand side spin means the white will tend to drift to the left i.e. hugging the cushion...

Now I will have to try the slow roll across the table with left side next time.

rekoons wrote:Then I guess the red hugs the cushion toward the green corner pocket, because after it hits the near jaw of the green side middle pocket (as seen from the pink spot) right hand side is automatically put on the white, and because of it running against the run of the nap this right hand side spin means the white will tend to drift to the left i.e. hugging the cushion...

Now I will have to try the slow roll across the table with left side next time.

Oooohhhhh! You are soooo close! The only thing that is incorrect is that you have your "rights" and "lefts" mixed up which is very easy to do because this whole idea is so, so counter-intuitive, left seems right and up seems down and day seems night. This gem of information is very much unknown by modern snooker players because so few players today have played or even know anything about English Billiards. This type of knowledge was critical back in the day for an English Billiards player so everyone knew of it when that game was popular. Sort of like very few people today know anything about blacksmithing or how to forge a horseshoe.

So I will just correct your lefts and rights here regarding that video clip specifically using the Green side of the table example.

First, we have to clearly define what "side" actually means to the ball as it travels. Seems simple but let's be clear. Best to do it by thinking of the extreme edges of the ball as we look at it when our face is down on the cue. If we are talking about an object ball with spin, then the left and right edges are defined as we look at it from behind. So if we strike our cue ball with "left" side, that means the LEFT edge moves faster toward the front of the ball (the direction it is traveling) and the RIGHT edge moves faster toward the rear of the ball. If we are now floating in a drone hovering over the table, we would see that LEFT side on the cue ball begins it spinning in clockwise direction. (Of course, you can see this if you have a spotted cue ball. Players do not normally think of clockwise and anti-clockwise spins because we can't really "see" spin at all with plain coloured balls on our table. So we just call it "left" and "right" based on our cue tip position; we don't call it "clockwise" nor "anti-clockwise".)

So getting back to the specific stroke, Red starts out around Pink spot, struck by White and now moving toward middle Green side pocket. Red strikes near jaw and physically, what happens is the RIGHT edge of the ball is hindered by the contact while the LEFT edge of the ball is unimpeded. This sets it spinning CLOCKWISE exactly the same as a cue ball that was struck with LEFT side, not right side as you stated. Then, the Red careens across the pocket and glances off the far jaw very nearly parallel to the Green side cushion. Again the RIGHT edge of the Red is impeded by contact with the cushion while the LEFT edge is unimpeded so the clockwise spin is amplified......we can say that the Red now has the equivalent of LEFT side applied as if it had been done by the tip of a cue stick. As the Red glances off the far jaw, it is now moving toward the Baulk cushion very, very close to the side cushion......let's just say about 10 mm away to give us some sort of visual imagery. Effectively, it is moving parallel to the side cushion and 10 mm away from it (remember this 10 mm....it will come up later) with what we will call LEFT side applied to it and traveling against the nap. Against the nap is the counter-intuitive part......the LEFT side on that RED will make it drift to the RIGHT, thereby moving the Red closer to the cushion as it travels. Over a short distance then, it will bump into the cushion again, and again, the right edge of the Red will be impeded by contact with the cushion, and so the LEFT spin is amplified even more and the effect just reinforces itself making that ball just stick to that cushion like glue. Again, this goes back to the conversation we had a while back about why it is easier to pot a ball that is touching cushion than a ball that is a short distance off cushion; exactly the same thing. It is a feedback loop.......sort of like if you hold a microphone in front of a speaker, or if you look into a mirror when there is a mirror behind you and you see infinite reflections.

So Rekoons, your thinking is correct but it boggles the mind how easy it is to get the "left" and "right" mixed up. To this day, anytime I face a stroke against the nap that I plan to strike slow speed, I think to myself, "Okay, it WANTS to drift to the LEFT, therefore I must apply a little LEFT to the White to hold it straight." If I don't do that, I miss the shot because the White goes wandering off on a curved line that I did not think about. To be clear about the amount of side to apply, let's consider the diagonal stroke, pocket weight (just enough power for the cue ball to reach the pocket) from the Black corner to the Yellow corner pocket. The amount of side you would apply would be just a tiny trace......say a half tip diameter. So to put actual numbers on that if it helps you......think that your tip is just average sized, about 10 mm. So half-tip of LEFT means you would strike the cue ball about 5 mm to the left of the perfect center point of the face of the cue ball. You already know this next point of course, but I will write it down in words.....if you are going diagonal across the table the other way, from top right Black corner pocket across Blue spot to the Green pocket, the ball will naturally drift to the RIGHT as it travels so then you must apply a trace, half-tip of RIGHT hand side to the cue ball to hold it traveling in a straight line (or at least reasonably straight.....snooker cloth is still thick and bumpy so the ball will "swim" through the cloth as it runs its line).

Now let's reverse our direction and play a Red from near the Brown spot but to keep our "lefts" and "rights" the same, let's play this Red into the Yellow side middle pocket. This Red strikes near jaw. The RIGHT edge of the ball is impeded by contact with cushion while the LEFT edge continues unimpeded and this again sets up a clockwise spin in the Red, exactly the same as the video clip example going the other direction. Red careens across the pocket and contacts far jaw and amplifies the spin, exactly the same as before. Now the Red is just slightly off the cushion, say, 10 mm (remember when I said "Remember this 10 mm?.....this is it) and basically moving parallel to the cushion. All the same as earlier. But now the difference is that this Red is traveling WITH the nap, not against it. So this Red has the equivalent of LEFT side applied to it and it is 10 mm off the side cushion and traveling parallel to it. What effect will the LEFT side have when traveling WITH the nap? Exactly like the "over-the-spots" drill, LEFT side on this Red will cause it to drift to the left and further away from the cushion. So it will never move closer to cushion, it will never rub its RIGHT edge against the cushion to set up that feedback loop to hug the cushion, and it will never fall into the Black corner pocket. (Well, we should never say never; anything is possible....I have seen tables terribly out of level so that any ball might roll anywhere but those would be very poor quality tables and they ought to be repaired and leveled properly.)

Science!




We will await BadSnookerPlayer to report back with his foregone conclusion about this counter-intuitive drift against the nap.

Oooohhhhh! You are soooo close! The only thing that is incorrect is that you have your "rights" and "lefts" mixed up which is very easy to do because this whole idea is so, so counter-intuitive, left seems right and up seems down and day seems night.

Dammit! I've actually misspelled, I meant the yellow pocket instead of the green, believe it or not...

Still, have to try i out myself!

rekoons wrote:

Oooohhhhh! You are soooo close! The only thing that is incorrect is that you have your "rights" and "lefts" mixed up which is very easy to do because this whole idea is so, so counter-intuitive, left seems right and up seems down and day seems night.

Dammit! I've actually misspelled, I meant the yellow pocket instead of the green, believe it or not...

Still, have to try i out myself!

Excellent! Then you do understand it perfectly! I only jumped to the Green side of the table because that is where we can exactly analyze the video evidence. Our earlier discussion had been on the Yellow side of the table so that was still in your head when you wrote your words.

Yes, you have to do this yourself. It really does seem like it cannot be correct until you actually see it happen. As stated earlier, it is not necessary to know about obscure information like this to be a good (or at least competent) player. But every once in a while, you are faced with a decision about how to play a particular stroke and knowledge like this can determine the difference between success and failure on that particular stroke.

Because of the nap of the cloth, a very strange (you might say mind-boggling) effect occurs. When you play the stroke with the LEFT side, again White will jump to the right initially like the other way, but then it will straighten out and it will not cross Blue spot. In fact, even though you put GENTLE LEFT side spin on it, the White WILL NOT come back to the left in an arc at all. It will begin to drift toward the RIGHT! When played at speed to just bounce off the Baulk cushion a foot, LEFT side spin will cause the White to drift to the RIGHT by about two inches (50 mm) by the time White strikes the cushion. If there is still any side spin remaining, it will still kick back toward the left a little bit just like normal.

I can confirm this phenomenon after trying it today, interesting.

Could not reproduce the nap effect on a diagonal shot from one black end pocket to baulk pocket however. was in a hurry so might try again next time.