Since this doesn't seem to be proprietary information of Lee Brett...it seems to be common knowledge in snooker...could someone provide some detail of what it is and why it helps? I'm always looking for incremental improvements and this could be helpful.
I will take a shot here....I have studied the grip as I think in pool it is almost as big of importance as in Golf....4 out of 5 Pro Golfers will tell you that the most important fundamental of Golf is "The Grip"
IMO the Pool grip falls into the same realm of what (in Golf) is called a "neutral" grip....The neutral grip in Golf actually uses both hands but it would apply to the grip hand (in pool) as well...(again IMO)
If you stand normal with your arms hanging down at your side, your hands do not face each other, nor do they hang facing straight back....They hang at a slight angle to your body......This is the "natural" hanging position that your hands will always return to...Any other position is a "forced" position...
If you grip your Golf club with a "neutral" grip the hands on your grip at impact will be in a more natural position and you will gain more consistency through impact....A grip that is "not" neutral will end up with at least one hand off of the normal rotation and you will end up having to force the hands into the correct position at impact...(hard to do consistently)
Intererestingly the "V" is also used in Golf as a grip alingment aid....There is some debate to this, but the "V" that is formed (by both hands) between the thumb and first finger in the golf grip should point to your "right eye".....some say to the nose...The main key is that they both point in the same direction....
I play golf right handed but play pool left handed........For me I grip the Golf club the exact same way with my left hand as I do to grip a Pool cue.....I use the last three fingers to grip the cue....My middle finger actually has the most contact with the cue....(and acts as the pendulum as Patrick suggested with the first finger and thumb)
The first finger and thumb of my left hand really don't do anything at all...I could have them both chopped off and still swing a Golf Club and Stroke a Pool cue.
The other reason I use the last three fingers is becuase just like in Golf it is the set of tendons that allow you to hold something firmly or lightly and still have free natural motion in your wrist. Your hand uses two indepentent groups of tendons....One is the pincher...first finger and thumb....the other is the last three fingers.....If you pinch your first finger and thumb together it creates tension in your wrist...the only way to relive the tension in your wrist (so it can move freely) is to relaxe the first finger and thumb....(try it by pinching your finger and thumb together and you will notice the tension in your wrist.
The last three or "golf" grip also puts the fulcrum of the cue directly in line with the middle of the wrist....Gripping the cue with the first finger and thumb puts the fulcrum in front of your wrist "off angle".....Basically if you go straight down the top of your arm....it goes to the "middle" finger. As it applies to the pool stroke...The first finger and thumb is out in front.
So for those of your that are Golfers....If you have a "correct" (Vardon Style) Golf grip....Take that same golf grip on your pool cue and then pull it up into a stroking stance...you will have a "neutral" pool grip.:wink:
I am 100% confident in this grip method....and the "V" method gets you to that "neutral" position....(weather the origonal teacher knew it or not)