Introduction
If you watch any movie or television show where the director is trying to convince you that a character is a “pool shark”, at least one bank shot is bound to make it into their highlight reel. In real-life play however, it is quite rare to see a player purposely play position for a bank shot.
Bank Shots are NOT Reliable
In the same way that adding side spin to a shot increases the number of variables, and therefore the difficulty of the shot at hand, the same is true of bank shots. With bank shots, you need to not only account for speed, spin, and cut angle, but also variables that you have less control over such as table conditions like cleanliness and humidity. Not all tables bank the same and even the same table will change how it banks over time.
As Earl Strickland stated “never bank a ball you can cut”. It is almost always better to take the cut shot over the bank shot because cut shots are simply more reliable. If you still need convincing, watch a few matches of the Derby City Classic Banks Division and see how many innings it takes world class professionals to pocket 5 balls in no particular order with only bank shots. It should make you think twice about choosing to play a bank when it isn’t necessary.
This isn’t to say that you should never go for the bank. There will inevitably be times when a bank shot is the best option you have available on the table. Whether it be due to positional requirements, table layout, or its just what your opponent left you with, bank shots will eventually come up and you need to be able to bank to become a well rounded player. There is nothing more satisfying than banking out of your opponents containing safety and punishing them for even letting you get to the table.
The Equal-Angles Rule
When it comes to aiming bank shots, the key rule to remember is that if a ball approaches a rail at some angle, it will rebound off that rail at the same angle. In other words, the rebound angle of a ball is equal to the approach angle. There are two common systems that use this rule as the basis for aiming bank shots.
The first system is the Mirror System. This is a common way to visualize banking by imagining a mirrored table that starts at the rail. Simply aim for the mirrored table’s pocket instead of a specific point on a rail and you should get reasonably close to pocketing the ball. The difficulty with this system is actually visualizing the imaginary table. Sometimes if you are at a pool hall where the tables are all in a line, you can aim for the other tables pockets that are closest to you with a slight adjustment for how far away the tables are actually spaced.
Another way to interpret this rule is with the Two-to-One System. This system uses the diamonds to help you calculate where on the rail you need to strike to pocket the object ball. The best way to do this is to find the two-to-one line that comes closest to the object ball that you are trying to make and aim at that point on the rail with a slight adjustment up or down the rail depending on how far the object ball is from that line. For instance, if the object ball we were trying to make was on the spot (2 diamonds up and 2 diamonds out) we could aim slightly below the 3 to 1.5 line.
Imperfect Systems
While these systems are a good starting point to get close to pocketing banks, they unfortunately fall flat when it comes to the actual execution of the shots. These systems really only work well when the object ball is struck at a medium speed and has enough space between itself and the rail that it can get a rolling spin on it. There are many other factors that come into play when shooting a bank shot including:
Cut Induced Spin
Spin Induced Spin
Rolling Spin
Speed
Table Conditions
At first, it may seem unfortunate that bank shots are not as simple to aim as the systems above makes them seem, but this can actually be advantageous as it gives us a wider range of ways to aim and hit a bank shot to help us manipulate the path of the cue ball and object ball in a way that is positionally advantageous. To become a strong bank shot player, you must learn how to deal with these variables and learn to manipulate them to your advantage.
Speed, Rolling-Spin, and Distance
The general rule of thumb passed down to players learning how to bank for the first time is that a fast speed bank results in a tighter rebound angle and a slower speed bank results in a wider rebound angle. While this is generally a true statement, it's important to understand the underlying mechanics of this phenomenon as it isn’t the speed alone that determines the change in the rebound angle.
The common misconception is that speed alone changes the way the rail compresses and rebounds the ball, but another important factor to consider is the amount of rolling spin that the object ball. An object ball with rolling spin banks wider and one without rolling spin banks tighter, but why is this?
The rolling spin that a ball has on it changes the changes the ball’s path after the initial bounce off the rail. This is very similar to how the cue ball initially starts traveling down the tangent line and its path only changes once the spin on the cue ball starts to grip the felt of the table to move it off that line. In the same way that speed changes how quickly spin takes the cue ball off of the tangent line, the same can be said for how long it takes the object ball’s spin to pull it off of the angle of rebound. If a ball is traveling at a lower speed, the spin will take almost immediately after the ball bounces off of the rail resulting in a wider bank. At a higher speed the spin taking is delayed and results in a tighter bank.
Conversely if a ball is struck at a slower speed, but it is close to the rail and therefore strikes the rail with no spin, there will be no spin to pull it off of the initial rebound angle resulting in a much tighter bank than what you would normally expect.
Here I set up two bank shots with exactly the same angle of approach and hit them at the same speed. The only thing that I changed is how close the object ball is to the rail. As predicted, the ball that is closer to the rail banks shorter than the one that is further from the rail. This is because the ball that is further from the rail has time to pick up a rolling spin whereas the ball that is closer to the rail has no spin at impact with the rail.
The takeaway here is that speed, spin, and distance all play a role in how a ball banks. Balls that are close to the rail bank shorter than balls that are farther from the rail. Additional speed not only tightens up the bank, but there may be less spin because the object doesn't reach a rolling spin before striking. Even if it does reach a rolling spin prior to impact with the rail, the spin grabbing the felt is delayed resulting in a tighter bank.
Side-Spin Effects on Rebound Angle
You can also manipulate the actual rebound angle of the object ball with the use of side-spin. This works similar to what side-spin does when it is put on the cue ball. The only difference is that you are limited in the amount of spin that you get onto the object ball since only a small percentage of the spin applied to the cue ball is transferred to the object ball. One thing to keep in mind is that the spin applied to the object ball is opposite of what you applied to the cue ball. You can think of the two balls as gears where as one spins clockwise, the other spins counter clockwise. This means that if you strike the cue ball with left spin, it will impart a slight right spin onto the object ball which will make it return slightly right of the natural rebound angle. You must also remember that the use of side spin means that you now need to account for all of the variables discussed in the side-spin lesson to ensure that it still strikes the point on the rail that you have chosen to aim for.
Cut Induced Spin
Not only does cutting a ball result in cut-induced throw, but with banks you also need to account for the slight spin that a cut imparts onto the object ball. In the above example from point "A" I am cutting a ball to the left to bank it into the side pocket. Even with no side spin on the cue ball, the cut itself imparts a slight right spin onto the object ball causing it to bank long. Coming from the opposite side, point "C", if I am cutting the object ball to the right, the cut imparts a slight left spin which causes it to bank short.
Stiffening / Widening Angles
We can use all of this knowledge to our advantage to stiffen and widen the angle of any given bank shot. The following are some examples of common situations where this may be necessary.
Stiffen the Bank: In the above example, the natural bank is unavailable due to the 9-ball that is blocking the 8-ball’s path to the pocket. In order to make this bank, we need to hit higher up on the rail, but that puts the angle of rebound in a place where it banks long of the pocket that we are aiming for. This means that we need to stiffen up the bank. To do this, we can hit the shot at a fast pace and with right spin. The right spin imparts left onto the object ball and the faster pace stiffens up the angle. Both the high speed and left spin on the object ball work together to stiffen up the rebound angle enough that we can still pocket the 8-ball.
Widen the Bank: Here, a ball blocks the natural point on the rail we would want to strike with the object ball to pocket it. We can move this point slightly down the rail further from the pocket and hit at a softer speed and with a bit of left. The left imparts right spin onto the object ball which in combination with the slow speed widens up the angle enough that we still pocket the object ball.
Avoid the Double Kiss: In this example, the cue ball is at a slight angle to the natural bank angle. If we shoot the 8-ball at a medium speed with the slight cut on the 8-ball to send it down the natural bank angle, the cue ball will float over into the path of the 8-ball. To avoid this collision, we can hit the 8-ball dead on instead of cutting it down the natural bank angle. This will allow us to change the path of the cue ball enough that it will not get in the way of the 8-ball. To do this and still make the 8-ball we need to strike with a hard stroke and a bit of right to stiffen up the angle.
Common Multi-Rail Banks
Conclusion
There are a lot of variables that go into a bank shot that make banking an inconsistent method of pocketing balls. If given the opportunity to bank a ball or cut it, it is almost always the right choice to cut the ball instead. That said, bank shots come up quite often in a game and are a great way to escape a containing safe. If you are comparatively weak at bank shot, then dedicate some time to them by taking ball in hand and shooting straight and slight angle bank shots. Try them at different speeds, spins, angles, and distances until you feel comfortable with and have a good understanding of all of the different variables to consider when banking. While it is necessary to be decent at banks, I feel that it is a mismanagement of time to dedicate a significant amount of time and effort trying to master them. Instead, simply try to get to a point where you are reasonable close to making most of the banks you shoot.
Completion Requirements
Read and comprehend this entire lesson
Try out each of the multi-rail banks
Practice straight-in & slight angle banks with ball in hand until you are favored to make them
Familiarize yourself with side-spin, distance from rail, speed, and cut angle effects on bank shots