The Three-Point Grip (not to be confused with the “Finger-On-Top Grip” or “Forefinger Grip”) is one of a number of grips that I was taught as part of my youthful training in fly casting. The Three-Point utilizes the thumb, the forefinger and the heel of the hand to produce a grip that heightens tactile awareness while still providing casting authority. This is my primary grip for much of my single-handed casting.
Some casters find that the Three-Point Grip is not ideal when using heavier (and often longer) rods, or those rods with highly flared handles. Casters with smaller hands and/or shorter fingers may also find that the Three-Point is not ideal, especially at longer distances. If you experience forefinger slippage or other control/comfort issues when using the Three-Point, I would suggest trying a different grip, such as the Thumb-On-Top.
If you are used to another grip, the Three-Point Grip may feel strange at first. Give it some time. Once you have made a cast and delivered the fly, you can slide your forefinger off the top of the rod handle to accommodate the different finger arrangement for stripping line. When it comes time to cast again, slide your forefinger back into position on the top of the handle. This action quickly becomes second-nature.
In our past fly-casting clinics, my father and I both noticed that many clients with wrist control problems on the backcast improved their control after switching over to the Three-Point Grip. Looking more closely, we noticed that with the Three-Point Grip, the rod lies at about a 20 to 30-degree angle from the hand’s center line rather than the nearly 90-degree angle as with the Thumb-On-Top Grip. This re-angling of the rod across the palm can aid in preventing the rod from being directed too far back due to wrist action when making a backcast.
I should note here that I also use more than one grip, depending on casting situation and rod type (two-hander, etc.). Because I grew up with it, and have somewhat larger hands/longer fingers, I find the Three-Point to be comfortable for most single-handed use, even big carries. But, I am also not locked into it as my only grip. I say learn the major grips (and their variations, if you have the time) and use what works for the situation at hand, so to speak.