Working out snooker angles is one of those aspects of the game that a lot of people talk about, but few understand in any depth.
You may hear commentators or players at the snooker club talk about half-ball, quarter-ball or the 90-degree rule and wonder what, exactly, they are referring to.
While some of these terms can sound straightforward, they don’t tell the whole story about angles, how they work and how they affect every shot you play.
An understanding of angles is fundamental to getting good at snooker. In this guide, we’ll be explaining snooker angles in depth, giving you all of the facts and tips you need to understand how to play snooker angles in all situations.
Why Does Learning About Angles Matter?
If no one has ever explained snooker angles to you, you may think that they aren’t that important, or that they are relatively self-explanatory.
You may even believe that an instinctive understanding of angles is just something that certain players are born with or that this can be developed simply through playing the game.
Successful players develop an instinctive understanding of snooker angles, but grasping the fundamentals of how angles work can speed up the learning process.
Without a solid understanding, you’ll find yourself frequently surprised or frustrated by the way that the cue ball behaves.
The Maths and Physics Behind Snooker Angles Explained
At the mention of maths and physics, you may be groaning inwardly, but you don’t have to worry. When it comes to snooker, maths and physics are your friends.
When snooker balls collide, they do so with near-perfect ‘elasticity’. This is a physics term that means the energy of the ball’s motion does not dissipate during a shot, either into heat or other forms of energy.
Put more simply, this means that snooker balls travel in a highly predictable fashion. If you have full control of the way that you hit the cue ball, you can predict what is going to happen.
This serves to underline the fundamental truth of snooker, that control of the cue ball, and in turn, correct stance and shot approach, determine around 90 percent of the chances of success of a shot.
There are many laws of physics and maths that can be applied to snooker, but the most important one to think about is the Law of Reflection.
This important rule was developed by the Ancient Greek mathematician Euclid and referred to the way that light behaves, but it can equally be applied to snooker.
In snooker terms, all you need to know is that the angle at which a ball hits the cushion is equal to the angle that the ball will bounce off that cushion (providing no side spin has been applied).
This useful law shows how logical and predictable snooker shots can be, even when you get into the more complicated forms of angles associated with the cue ball hitting the object ball.
Key Snooker Angles Explained
Very few shots in snooker are played ‘full on’ with no angle. Usually, you’ll be playing an angled shot, which means that the cue ball hits the object ball with a degree of ‘cut’.
The thinner the contact, that is the more ‘glancing’ the impact, the bigger the angle that the struck ball will travel along, measured against the cue ball’s trajectory.
The Tangent Angle
Since control of the cue ball is one of the most important factors in snooker success, players need to be able to predict the direction of the cue ball’s travel after contact. This is where the tangent angle comes in.
This angle is the natural angle that the cue ball will take after it contacts the object ball, and the line of its travel is known as the tangent line. If there is no spin imparted on the cue ball, it will always follow the tangent angle along the tangent line.
The Fullness of Impact
You may have heard snooker commentators and players talk about different levels of contact and angle as fractions of ‘fullness’. This is a useful rule of thumb that can help you understand angles.
The fullness of an impact refers to the extent that the cue ball overlaps the object ball when it makes contact.
So a contact that is full-on will be a ‘full ball’ whereas if the cue ball covers roughly half of the object ball when viewed from your perspective, it is a ‘half ball’ contact.
This leads to a useful rule of thumb that can help you to estimate the angle. A full-ball impact has an angle of 0 degrees and you simply add 15 degrees each time you reduce the fullness by a quarter. This gives you a working framework of four different levels of fullness and the associated angles.
The 30-Degree Rule
While the rough rule of thumb detailed above produces some useful measures, the most important of these degrees of fullness is the half-ball, which leads to the 30-degree rule.
The rule states that when a cue ball hits an object ball with a half-ball contact, the deflection of the cue ball will be at an angle of 30 degrees from its starting path.
Since the half-ball shot is exactly halfway between a full ball shot and missing the object ball entirely, it is the most useful angle to be aware of, and the 30-degree rule can be a great place to start when improving your positional play.
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The 90-Degree Rule
The stun shot is often used by snooker players to control the position of the cue ball. With a stun shot, the cue ball is struck slightly below the centre. When this shot is played full ball, the cue ball ‘stops’ on impact with the object ball, remaining close to the point of impact.
This is obviously useful in some circumstances, however, when the cue ball hits the object ball at an angle in a stun shot, it behaves differently. In these circumstances, the cue ball will always travel along a line at 90 degrees to the object ball, regardless of the angle at which it struck the object ball.
This is the 90-degree rule, and while it may be slightly counter-intuitive, it is a very useful rule of thumb that helps snooker players maintain control of the cue ball when playing a stun shot.
How to Play Snooker Angles
So much for the theory of angles, but how can you put angle awareness into practice? Here are a few hints and tips that can help you to harness the power of angles in your snooker play.
Take Care with Thin Cuts
One of the most important rules to remember is that very thin contact shots can be difficult to predict. In fact, we know that when a contact is thinner than a quarter fullness, it becomes hard to estimate even how much of the object ball is being contacted.
At the same time, the angle of the cut increases more dramatically and so small errors can be magnified.
Shots with contacts of less than a quarter ball require a lot of practice to master and ideally should be played as little as possible.
Check the Clock
If you need an angle visualisation tool that is a little more practical than the ‘fullness’ model, try thinking about a traditional clock face. You can even glance at your watch if it helps.
Assume that 12 o’clock is a 0-degree angle and each ‘minute’ on the virtual clock is worth 6 degrees.
This means that the eleven and one positions on the clock are at 30 degrees (half-ball) and the ten and two marks are at 60 degrees (1/8th ball). You can then use these markers to estimate angles that fall between to help you fine-tune your shot.
Use the Ghost Ball
Another useful alternative to the fullness method is the ‘ghost ball’ concept. First imagine a line that runs from the point where you want the object ball to travel to (usually a pocket) to the centre of the object ball.
Extend the imaginary line a little further beyond the object ball and try to picture a ‘ghost ball’ fully on this line and in contact with the object ball. Aim to hit the centre of the ‘ghost ball’, thus effectively turning an angled shot into a much simpler ‘full-ball contact’ with the ghost ball.
Spin and Snooker Angles Explained
Up until this point we have assumed that your shots are being played by striking the cue ball in the centre, with no deviation horizontally or vertically.
Of course, this is rarely the case in snooker, as most shorts are played with some degree of deviation or ‘spin’, but the addition of spin to the equation complicates the way that we calculate angles in snooker.
Angles and Spin
There are several forms of spin, but most are variations or combinations of the four basic forms of spin. Hitting the cue ball left or right of centre, for example, will cause it to deflect further to the left or right when it hits the object ball than a cue ball hit with no spin.
Hitting the cueball above the centre will impart topspin, so that the cue ball rolls forward at impact, while shots below centre create backspin. The further from the cue ball’s centre that you strike, the greater the degree of spin.
We know that a cue ball that is rolling normally will deflect from the object ball on a line determined by the tangent angle. But when spin is applied to the cueball, this is not the case.
For instance, if the cue ball has been hit with topspin or backspin when it hits the object ball, it will not deviate along the tangent line, but will instead take a different tangent angle, rolling ahead or behind the original line.
So, when players are using any degree of spin on a shot, they have to make adjustments to the angle of the shot to allow for this, as the cue ball will impart some spin to the object ball and cause it to travel along a slightly different line to the tangent line.
As well as being able to make these calculations to ensure optimal cue ball position when making a shot, skilled players can also use spin to change the line along which the object ball travels, in order to make a pot or play a shot that otherwise would not work.
For example, you may be in a situation where you are unable to hit the object ball at the correct potting angle because another ball is blocking that line. If you can still hit the object ball full-on, however, you can use spin to generate the correct potting angle.
A rough rule of thumb in these circumstances is to use the following amounts of side spin according to the required potting angle:
| Potting angle | Spin |
| 15 degrees | 20% |
| 30 degrees | 40% |
| 45 degrees | 55% |
| 60 degrees | 70% |
| 90 degrees | 80% |
Understanding the interaction between spin, angle and object ball line is the key to mastering snooker angles.
Skilled players will adjust the angle of a shot to allow for any spin that they are imparting on the cue ball, and in other circumstances will adjust the level of spin they generate on the cue ball to change the potting angle on the object ball.
Conclusion
To become a skilled snooker player, your understanding of angles and how to manipulate them must be instinctive. While knowing the theory can help, consistent practice is the only way to master angles and incorporate them into your game.
