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Kicks and Banks - Part II (complications)
© Copyright 1999, Jim Loy
This article is now in three parts: Part I
(calculating), Part II (complications), and
Part III (putting it all together).
Complications
Now, we must deal with the complications. It is good to be aware of
these complications. But, you don't normally have to think about them, except
when you want to shoot with extra speed or side English.
Complication #1 - Deadness of the rail: The rail is not a
mirror which is reflecting light beams. So, our statement about the angles
being equal is usually false. It is close to the truth, but is not exact. The
rail is relatively dead. So, the cue ball will curve, after hitting the rail.
This makes the shot go long (to the right in the diagrams). You aim short (a
little to the left, in the diagram) to compensate for this. How short? The
point of aim is Y' in the diagram. This is the image of Y, but on
a line between the diamonds. You imagine an invisible (imaginary) diamond
between two of the real diamonds. The real diamonds are inset from the inside
of the rail, for just this purpose. They are roughly the right distance to
compensate for this curve.
Complication #2 - Balls are not points: Pool balls are not
tiny points, but fairly large spheres. In the diagrams, your cue ball hits the
rail before it gets to point Y (shown in above diagram). So, it does not
follow the path from Y to the object ball. The real contact point is not
the point Y in these diagrams. Apparently, the Y' compensation
(aiming at the diamond) deals with this effect, too, when the object ball is a
long distance from the rail (near the opposite side rail). But, this effect
overwhelms the curve effect, when the object ball is relatively close to the
rail, as it is in these diagrams. This becomes absolutely obvious, when the
object ball is very close to the rail. But, then you don't need any diamonds to
get the hit you want on the object ball. So, you aim to the left, to compensate
for curve, and you aim to the right to compensate for the large cue ball
hitting the rail before it hits the aiming point. It takes some judgement to
guess where to aim between these to effects. If the object ball is a long way
from the rail, you can ignore this effect, because aiming at the diamond
(imaginary or real) already deals with it.
Complication #3 - Side English: Side English (caused by
hitting the cue ball on the left or right side with your cue) affects the angle
off the rail. In fact, this is the most noticeable effect of side English.
Accidental side English is probably why kicks are often more difficult than
banks. Relatively little accidental English is transferred to the object ball
on a bank. Concerning kicks, there are two kinds of English, running English,
and reverse. Running English (right English in this diagram) is the natural
English that is that same English that the cue ball would acquire just by
hitting the cushion from an angle. Such English is helpful in two and
three-rail kicks. For this one rail kick, it makes the shot go longer, farther
down the rail. You can compensate by aiming short. Reverse is the opposite
(left English in this diagram), unnatural English. It tends to make the kick go
short. And you can compensate by aiming long.
Note: Reverse English is relatively unpredictable. One of the things
that makes it unpredictable is slide off the rail. If the path of the cue ball
is almost parallel to the rail, reverse will have little effect; the ball will
slide on the rail, and will not grab. The same thing happens to balls with no
English, to a lesser degree. There are shots where this effect is very useful,
as the cue ball will probably still have reverse when it hits a second rail.
Complication #4 - Draw & follow: Draw (low ball) and
follow (high ball) effect the curve on the cue ball. We normally use a normal
follow when shooting a kick. This is the follow that the cue ball acquires just
by rolling on the cloth. Extra follow will increase the curve. And you can
compensate by aiming short. Draw will make the cue ball curve in the opposite
direction, back towards you. And you can compensate by aiming long.
Complication #5 - Ball speed and rail compression: Some
kicks are shot with a medium-soft speed. This is the speed where the diamonds
are most useful. You use medium-soft speed, with normal follow, no side
English. And you aim at the diamond (maybe an imaginary diamond between real
diamonds). Faster speed shortens the angles (like reverse or draw does). And
you can compensate by aiming longer (quite a bit longer at some speeds). To
some extent, this is due to the fact that the cue ball is sliding all the way
to the rail, and does not have normal follow. But, a more important effect is
rail compression. See the diagram, above right. The rail changes the path of
the cue ball, like a mirror reflects light. But the rail also moves a short
distance down table (to the right in these diagrams). See the deformation of
the rail in this diagram. When the rail springs back, it pushes the ball back
the way it came (tiny arrow on the rail in this diagram). This effect can
actually become fairly predictable.
Some people consistently shoot banks and kicks at just the right speed
(shoot fairly hard, "crisp" might be the right word) so they can aim at the
contact point instead of the image at the diamonds (Y instead of
Y'). They do this because they have found that they can get a very
consistent angle in this way. Their banks and kicks are very predictable. Some
other people shoot their banks extra hard (and compensate by aiming longer).
But sometimes you do need a different speed. So you should probably be aware of
(and practice) all of the complications on this page.
Addendum:
Complication #6 - Near a rail: In this diagram, we see a
common situation. We want to bank a ball that is near a rail. The angle will be
different from an ordinary bank, because the ball will slide on the cloth, all
the way to the rail. It will not roll, even if we shoot soft. This makes the
angle sharper, it makes the rail less dead. So, you have to make the ball go
farther down table before it hits the rail. Sometimes you have to aim a half
diamond farther down table. This situation affects a kick, when the cue ball is
close to the rail. You have to aim farther down table, or use extra follow, or
extra running English, or some combination of these, depending on your
judgment, to compensate for the slide.
Another complication is the table conditions. A dirty table is probably
shorter. Humidity may affect the angles; it certainly affects table speed.
Also, elevating your cue (shooting over a ball) may have all kinds of
disastrously consequences.
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