Pivot Aim Systems
There is an ever-growing family of aim methods that begin with the full line or some edge-to-edge or edge-to-center line followed with pivoting the cue stick or body from that line to determine the final shot line. Their complexity can be astounding and off-putting. One of the simpler, more effective methods will be given here:
1. Aim along the full line at the object ball's edge with both right and left hands one tip's width outside center ball. (For the accompanying diagram, the player would aim on the right side of center ball toward the right edge of the 2-ball.)
2. Leave the bridge hand in place and pivot the cue stick to center ball with your stroking arm only. This provides an approximation of true geometric aim for most shots-except this diagram, as this method is not designed for absolute half ball hits.
Limitations of Pivot Aim:
1. Changing any factor in the pivot itself, such as changing between lengths of cue stick or bridge length and etc. will alter all calculations making them unwieldy. Pool balls are the same sizes on all sizes of table and the geometric aim systems represent the most consistent opportunity for correct aim.
2. Aim and pivot methods can provide a fine frame of reference to develop sighting and feel for aim. The professionals who aim using these methods, however, do so with their eyes then step to their stance along the final aim line without any physical pivot. Twisting the cue and/or pivoting the body to build the stance in place are often detrimental to the final straight stroke that is desired.
Other Aim Systems
A variety of other systems exist, most of them refinements to the systems presented thus far, though like many of the pivot aim systems, most of these alternatives and "enhancements" are fallible. Two examples will suffice:
"Holy Light System" (and "Shadows System") -- Mark specific light reflections (or shadows) cast on the pool table for convenient cue ball point and contact point guides.
Limitation--Indoor light sources have to be precise and measured and shadows change through the course of a day. Changing tables or lighting could ruin these systems.
"Shane Van Boening System" -- Shane Van Boening is a top player on the men's pro tours. He developed a system early in his playing career where he uses one edge of his cue stick for most cut shots (or its dead center for full and near full shots) and then aims that edge or center at either edge of the object ball. The half ball hit in this manual would be aligned as "left edge of cue stroked toward right edge of ball".
Limitations--Van Boening's measurements are approximations. Also, most shots require a refinement from the exact edge of the object ball to a spot closer to its contact point as discussed under fraction aim.
Over a dozen other methods could be presented, most of them theoretical and breaking down quickly when a geometer compares them to real angles on the pool table.
[Editor's note: Point and pivot, center-to-edge and similar methods are not for beginning players. The experts who use them, myself included, do so with our eyes before bending to shoot and not with actual swiveling of the cue and/or body, which can easily throw shot making off.]
Following long experience teaching students with varying skill levels from rank beginners through the professional level, and working through attendant factors such as collision- and spin-induced throw, and canvassing many professionals about their aim systems, the author has concluded that the contact point and parallel aim systems provide the best results for the beginning to intermediate player. Experts can add pivot systems to their methods if they recognize their physical and geometric limitations.
CAUTION: Most experts aim then stroke straight along the shot line or nearly so. Most amateurs instead aim incorrectly due to vision or aim method shortcomings or both. They then (usually) swerve toward the correct shot line with the forward final stroke.
In other words, the beginner's stroking arm reaches out to the correct line though their aim and stick in space are twisted to begin. This twisting hampers an ideal stroke, so if the simple shots in this manual prove difficult to accomplish, it is time to have a quality instructor review stance and stroke.
[Editor's note: I'm as near as your e-mail and am happy to help.]
Aim Primer 1: How To Use The Aim Manual
Aim Primer 2: Glossary Of Key Terms
Aim Primer 3: Stance And Stroke
Aim Primer 4: Instinct Vs. Fraction Aim
Aim Primer 5: Contact Point And Half Ball Line
Aim Primer 6: Fraction, Edge-To-Edge, Perfect And Ghost Ball Aim
Aim Primer 7: Ghost Ball Vs. Contact Point Aim
Aim Primer 8: Parallel And Pivot Aim