Billard CaramboleCourse, systems & practice
+ if your table "runs long" (lands beyond), − if it "runs short". Applied to the System 4 calculator.
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Spin is the rotation the tip gives your ball when it strikes it anywhere other than dead center. It is not a system: it calculates nothing. It is a technical detail that is used everywhere — in the typical shots, System 4, the Conti system, the one-cushion system and the scale points — and it explains why the same ball does not leave the same way depending on where you strike it.
This page gives the basic rule (hit high, add spin from the side, by levels), says what it changes at the cushion and on ball 2, how to dose it, and how to measure it on your own table.
For almost every shot, you hit your ball high: above the center, on the axis, with no spin. It picks up speed, moves forward and carries on to the end of its run. This hit is your level 0.
When you need spin, you start from this high hit and shift the tip one step per level, to the left or to the right. One step is one tip. Level 1: one tip to the side. Level 2: one more tip to the side, still at the same height. Saying "I'm putting on two spins" means hitting at level 2: the higher the level, the more spin you put on.
The cue ball seen from behind. Each square of the grid is a one-tip step; the circles are the spin levels, from 0 (high, no spin) to 5 (maximum spin). Here on the left; on the right, it is the same scale mirrored (pale circles). A diagram of the principle, not to scale.
Why do it this way? Because the idea is that the ball always moves forward: hit high, it keeps its speed to the end. And the spin you add from the side, when it runs with the ball at the cushion, speeds it up further and lengthens its path (see "At the cushion" below).
After level 2, you cannot go any further to the side without a miscue: at that height the ball is too narrow and the tip slips. So you go down one tip instead of shifting: that is level 3, then one more tip lower for level 4. Lower down, the ball is wider, and you can shift one tip to the side again: that is level 5, almost at the height of the equator. It is the maximum spin; beyond it, the miscue.
Offset is counted in tips: 1 tip is the width of your cue tip (10 to 12 mm, see Equipment), on a ball 61.5 mm across. Half a tip puts the edge of the tip on the center of the ball: that is the moderate, repeatable side spin of the glossary.
When you prepare a shot you make three independent choices. Normally the height does not change (you hit high): you mostly adjust the side and the fullness. Mixing them up is behind many mistakes.
| Setting | What you choose | What it changes |
|---|---|---|
| Height of the hit | above the center, at the center or below | the forward or backward spin: after contact the ball follows, stops or comes back |
| Side of the hit | left, right or on the axis | the side spin: the exit angle at the cushion and a slight deflection of ball 2 |
| Fullness | from thin to full | the direction ball 2 takes and the deflection of ball 1: not a spin, but its result blends with the spin's |
This is your basic hit: above the center, on the axis. The ball spins in its direction of travel, picks up speed and keeps going after contact. It is also the height used for the natural shot and the follow shot, where the fullness taken is what changes the behavior: the closer to full, the more the ball follows. It is the starting point of every setting: you measure what each spin changes by comparing with it.
It is the exception to the "hit high" rule: you only use it when you want the ball to come back. The ball spins against its direction of travel. After striking another ball it comes back toward you. It is how you get back into position without "climbing" into the other balls. Too far from ball 2 and you have to hit hard to make it come back; too close and a miscue lurks (see Typical shots).
You start from the high hit and move one tip per level: sideways at levels 1 and 2, downward at levels 3 and 4, sideways again at level 5. The ball leaves practically on its line; the effect shows afterwards: at the cushion it changes the exit angle, and on ball 2 it leaves a small deflection. It is the main tool for opening or closing a path in the cushion systems. With a big spin, the cue deflects the ball slightly before it even rolls (see below).
Height and side can be stacked. The usual case is high and to the side, like the levels in the diagram, for example high and left for the closed angle of the scale points, below the center and on the opposite side for the open angle. Add one element at a time while learning: you will know which one did what.
When the ball reaches a cushion, its side spin rubs against it. If the spin goes the way the ball slides along the cushion, it helps: the ball leaves faster and its path lengthens — that is running spin. If it goes the other way, it holds the ball back: it leaves slower and straighter into the table, and the path shortens — that is reverse spin.
That is why, at a cushion, running spin speeds up the ball and increases its distance, while reverse spin slows it down. Over a path of several cushions, running spin also keeps the ball steadier: one more reason to prefer it, with a ball hit high that keeps moving forward.
To know which one you have: stand facing the cushion the ball is about to hit. The ball arrives moving toward your left or your right along that cushion. Spin on the same side runs with it; spin on the opposite side works against it.
Same cushion, same arrival angle, three exits. The ball arrives from the right: spin on the left runs with it, spin on the right works against it. The angles are indicative — the real difference depends on the cushion, the cloth, the speed and the amount of spin.
Spin acts mostly at the cushion. On a direct shot, where your ball goes to ball 2 without touching a cushion first, it hardly changes anything: no need to add any. In general, only use it if the shot calls for it, especially in right-angle shots off the cushion(s).
Over a path of several cushions, varying the spin changes the ball's direction little but its speed clearly: it is therefore an arrival adjustment, which counts in the balance of speeds between your balls. A maximum spin helps the ball keep its speed at the cushions.
The two balls rub where they touch. Your ball's side spin gives ball 2 a small opposite spin (that is the glossary rule) and deflects it slightly from its line, more so the slower the shot. With a strong spin you will feel it on a thin hit or when ball 2 has to arrive very precisely.
When you offset a lot, the cue pushes the ball slightly to the side opposite to your offset, before it even rolls. With a small spin you won't see it; with a big spin you need to aim slightly toward the side you offset to. The right compensation is found at the table by repeating the same shot.
The spin wears off on the cloth: it acts most at the start of the path. A spin given for a nearby first cushion will not weigh the same on a distant cushion — dose it according to distance and the number of cushions. On new cloth, reverse spin straightens the path less after the cushion: you then have to play a little thinner and put on more spin.
Level 5 is the lowest and the most lateral of the scale, almost at the height of the ball's equator, that is, its center: the side spin is strongest there. The French federation manuals say the same: for a maximum spin, you hit at the height of the equator. If the ball is far from ball 2, it recovers its natural motion before contact; the chosen height therefore does not change the deflection of the shot. Keep it for shots that need it.
Dosing is counted in tips. The site already gives a rule for System 4: one tip of spin shifts the arrival by one diamond if the carry-over was positive, by half a diamond if it was negative. Elsewhere there is no universal table: the same offset does not give the same result depending on the cloth, the state of the cushions, the speed and your tip.
At equal offset, what changes the result: the speed, the distance before the cushion, the state of cloth and cushions, the tip and chalk, and the fullness. The only reliable method is therefore to measure on your own table with an always-identical shot — as for the Conti setup in Test your table — and to write down your own scale (exercise 3).
Do them in order. Each success criterion is a suggestion: adjust it to your level, but always keep the same shot and the same speed from one attempt to the next.
Goal: know exactly where the tip touches.
How: Chalk the tip well, place it near the ball at the chosen spot and play a soft shot. A small chalk mark stays on the ball where it was touched: compare it with the spot you wanted. Change the level with each series (0, 1, 2 high, then draw).
Criterion: 8 shots out of 10 within half a tip of the intended spot.
Goal: feel what the height of the hit changes.
How: Hit ball 2 full, from the same distance and at the same speed: first at the center, then half a tip above, then half a tip below. Note where your ball stops after contact.
Criterion: three shots in a row that stop within the same 10 cm zone, for each of the three heights.
Goal: measure what spin does on your table.
How: Fix a starting point, a cushion to hit and a speed. Play at level 0 and note where the ball arrives (in diamonds on the next cushion). Then repeat at levels 1, 3 and 5 to the left, then to the right. Three tries per setting: keep the most frequent value. With a strong spin, check whether you need to aim slightly toward the side of the spin to reach the same cushion point.
| Setting | Arrival noted (diamonds) | Difference from level 0 |
|---|---|---|
| Level 0 (high, no spin) | … | — |
| Level 1 left | … | … |
| Level 3 left | … | … |
| Level 5 left | … | … |
| Level 1 right | … | … |
| Level 3 right | … | … |
| Level 5 right | … | … |
Criterion: a complete table whose differences grow with the spin. If they do not, your stroke is not consistent enough: go back to exercise 1.
Goal: see that spin does not weigh the same at every speed.
How: Take one setting from exercise 3 (for example level 3 left) and play it at three speeds — soft, medium, firm — from the same point toward the same cushion. Note each arrival.
Criterion: you can say, before playing, whether the difference will grow or shrink when you change speed.
Goal: recognize the direction of the spin relative to the cushion.
How: Same cushion point, same arrival angle: play a running spin, then a reverse spin. Watch the lengthened path and the shortened path of the diagram.
Criterion: four times out of five, you call the right direction before playing.
Goal: choose the spin before playing.
How: Place the three balls so that the shot with no spin narrowly misses ball 3 (for example the position in the “Side spin” diagram of Typical shots). Choose the side and the dose, announce them, then play.
Criterion: three successes out of five with the dose announced before the shot.
⚠️ The mechanisms described here (spin, friction at the cushion and between the balls, cue deflection) are physics common to all billiards; the vocabulary (the tip as a unit, follow, draw) is the site's. The diagrams show a principle, not a measurement: real differences depend on your table, your tip and the speed — check them at the table, as with the systems. The writing and the diagrams are our own.