Bob Jewett said:
I think the last part is true, but my feeling is that anyone who undertakes to describe a system has a duty to include enough details that the student will know what he needs to worry about. I've seen dozens of systems that were described so badly that it would be impossible for two different people to implement them in the same way.
How true!
Wei admittedly was just trying to share a new system after having just having been taught it (by Miguel) two days earlier - and did not give himself enough time to understand exactly why it works (or when doesn't).
What struck Bob threw up red flags for me as well - since the slight difference (center vs 1/2 tip high) in tip placement has no significance to the cue ball action by the time it connects with the first rail (the cue achieves a natural roll in both cases) - what is the purpose? A speed change would MUCH better explain how to achieve a different arrival point on the third cushion than the proposed change in tip placement.
Based on his diagram, the cue ball paths to the first cushion are roughly parallel in all 4 scenarios (yellow and white, A and B). If we assume that the system calls for the same exact speed for all attempts, then we can imply that the amount of induced english from the cushion is the same for all the cases (due to the identical incidence angle). It follows (and his illustration depicts) that we see similar reflection angles (to the second cushion) which are roughly parallel to each other. What might strike a probing 3-cushion student is this: "Why do his lines from the 2nd to the 3rd cushion 'coincidentally' converge to the same point?"
It would be reasonable for one to expect that the paths away from the 2nd cushion should be parallel to each other because the angles coming into the 2nd rail are parallel and the induced english the first cushion are identical. (I personally don't use the system, but) I can offer a good explanation explanation on why Miguel's system might work (as illustrated by Wei).
A major difference between the different cases is the travel distance between the first cushion and the 2nd cushion (yellow A = ~1+ diamond - white B = ~4+ diamonds). The induced english derived from the 1st cushion gradually wear off as the distance the cue ball travels increases - explaining why "white B" has less english on the 2nd cushion than "yellow A", in Wei's diagram. Note that for the system to really work, one must have faith that the differences in the amount of english removed will match the 2nd cushion offsets perfectly and to the correct degree.
These particular types of shots with no english are very sensitive to speed because of the induced english the cue ball receives from the 1st cushion (and then loses on its way between the first and 2nd) are strongly tied to the characteristics of friction of the rails and the table surface. A player of 3-cushion can benefit by incorporating a feeling for these dynamics when shooting these kinds of shots (as opposed to blindly putting all of their trust strictly into the diamonds).
Because there exist so many poorly described systems, I think everyone owes it to themselves to attempt to explain why any given system works - take it apart to see where its limits and sensitivities are. If you just blindly learn and accept a "system" you might prove to be very effective on one table and then be at a total loss when faced with a different set of conditions on the next table. But if one goes through the exercise of explaining (to themself) WHY something works, then they'll be better prepared to improvise when faced with slighly different positions.
A "system" player naturally develops the tendency to alter their stroke subconsciously in order to "cause" a particular system work for them regardless of where "The System" originally directed them to aim. We're talking specifically about "diamond systems", but the context can be extended to a wider scope. The desire to score a point is such a powerful suggestive force, it is easy to ignore the subtle adjustments one makes in execution as they think about achieving the desired result - and then attribute more credit to "The System" than it probably deserves. I hear a lot of players say that systems help to build confidence. For me, the real confidence builder is being able to "take full credit" for a point scored.
