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Two Rail Kicks and Banks

© Copyright 1999, Jim Loy

The two rail kick or bank (left) bears some similarity to the one rail kick or bank (right). One such similarity is that if the rails were mirrors, and the path of the ball were a light beam, almost the same formula works for both. For the one rail kick, the formula is y=ax/(a+b). For the two rail kick, the formula is y=a(x1+x2)/(a+b). The x1+x2 is the distance between the balls, parallel to the first rail, just like the one rail kick. But this distance is not direct, being from the cue ball to the second rail to the object ball. Many of the ideas that we saw for the one rail kicks and banks (see Kicks and Banks) will apply here.

One important feature of the two rail kick is that the cue ball's path going into the first rail is roughly parallel to its path coming off the second rail. Theoretically, if the paths were light beams reflecting off mirrors, these two paths would be exactly parallel. In reality, parallel is a good first approximation of the final path.

When shooting a two rail kick or bank, you are either going into the long (side) rail first or the short (end) rail first. The short rail first shot is called a "plus 2" which I will cover later. The long rail first shot is a simplification of the three rail kick or bank.

The Basic Diamond System:

I will start by showing you the basic diamond system. See the diagram. We have three sets of numbers, the "cue ball position numbers," the "first rail numbers," and the "third rail numbers." These numbers have been selected so that the first rail number + the third rail number=the cue ball position number. The first rail number and the third rail number are measured from the second rail. The cue ball position number starts with position of 5, the corner pocket, as shown in the diagram. Next to 5, along the long rail is 4.5 at the first diamond, then 4, then 3.5, etc. As you see, there are two diamonds per whole number. The numbers on the end rail go 6, 7, etc., without skipping any diamonds. This system does not tell you where you are going to hit on the second rail. You have to judge that for yourself.

That is interesting information, but how do you use it? Well, in the diagram, we have a situation where we want to hit the red ball after two rails. The cue ball is at 5, and the object ball is at about 2. 5-2=3. So we aim at diamond 3. It is as simple as that.

This shot is meant to be shot with relatively slow speed and running English (see Kicks & Banks - Part II (complications) under side English). Shooting harder will shorten the shot. Notice that we aim at the diamond, not at its image on the rail. Also notice that the shot goes toward the diamond on the third rail.

If the cue ball is out in the middle of the table, you will have to take a little more time adjusting your estimated track to the first rail to see what the cue ball position number and first rail numbers are. Then you subtract and you have the third rail number. Is that where the object ball is? If not then try another track and subtract again. If the object ball is not at the rail, you will have to use judgment, as this system does not tell you where you will hit the second rail.

Quite a few people multiply these numbers by 10. In the diagram, the cue ball would be at position 50, and the red ball is at 20, and we aim at 30. They say that this is more accurate. But, it is just a matter of personal preference. If you don't multiply by ten, you will use fractions or decimals, and get the same results.

Banking an object ball two rails requires a different aim, as you can get very little running English on the object ball until after the first rail.

The Plus Two:

For the Plus Two shot, the diamonds on the end rail are numbered 3, 5, and 7 (see the diagram), with the even numbers between them. The corner pocket, near 2, is numbered 1. On a carom billiards table, you can hit number 1. But in pool you can't hit number 1, because the pocket is there. To shoot the shot, you measure the number of diamonds between the cue ball and the object ball (along the long rail behind the cue ball). And that distance is the first rail number that you aim at, with relatively soft running English (see Kicks and Banks - Part II (complications) under side English). Number 2 is closer to the rubber part of the rail than the diamonds are.

In the diagram, you can also hit a target on the right end rail. The distance between the two balls, in number of diamonds, is measured around the corner.

The above system is not very accurate. Some people vary the amount of running English to compensate for this. Others seem to vary the aim somewhat (up to a half a diamond), depending on where the two balls are.

This shot goes from a diamond to a diamond. If either ball is away from the side rail, your measurement between diamonds will be more complicated. You will have to sight to the rail to find the diamond. Banking an object ball two rails requires a different aim, as you can get very little running English on the object ball. A faster speed seems to make this shot longer, as the cue ball goes farther down table off the first rail.

If the distance between the balls, in diamonds, is 1 or 0, then aim at 2 (or even closer to the pocket), and use reverse English.

I suspect that the reason this shot is called a Plus Two, is that when you aim near the pocket, you end up hitting a point about two diamonds down table. You just add +2 to the diamond where your cue ball is.

As I said above, the two spot (red in the diagram) is closer to the rubber part of the rail than the other spots are. I have taken this idea from Byrne's Standard Book. I think he shows that the two spot is the midpoint on a line from the three spot to the center of the pocket. This is apparently some kind of adjustment, maybe because the cueball does not have time to curve off the first rail.

Dr. Cue makes adjustments in the running English, depending on which spot he is aiming at:

Addendum:

parallelParallel: With two rail banks or kicks, a parallel method (related to method #3 in Kicks and Banks) is particularly useful. In the diagram, the cue ball's path into the first rail, and out of the second rail are parallel (ignoring the many complications, such as spin and ball speed). These paths can be estimated just by imagining parallel paths. But a more reliable way is to find the point midway between the two balls, and imagine a line from that point to the pocket toward which you are shooting (actually to the point where the two rails intersect. This line is also parallel to the two cue ball paths that I mentioned. So just aim parallel to this line. This is especially accurate for short shots. For longer shots, the various complications become increasingly important. In the basic diamond system above, this parallel method is a whole diamond off.

short and longShort and long: An interesting bit of confusion comes up with the two rail banks and kicks. From some viewpoints, aiming short would seem to come up long, and aiming long would seem to come up short. Mainly, this depends on how you define "short" and "long," or which direction you are facing. If the target ball is near the opposite side rail, then you may observe that aiming long comes up long, because now we are concerned with how far down table the ball goes, and "long" means farther down the table. In the diagram on the right, I use "long" to mean farther down table. And so, aiming short comes up short, and aiming long comes up long.

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