[Yoda]

What exactly does it mean to have a "flat left wrist" at impact? Is this in reference to the #3 Accumulator... meaning no bend only uncock and roll or that the wrist faces the target, or what? I play with a relatively strong grip and my left wrist seems bent at setup or at least it is not facing the target. Should I only be rotating it and not bending it (is that possible with a strong grip) when I take my grip?

The key alignment is that the Clubshaft be 'in line' with the Left Arm. This assures the Rhythm of the Stroke, i.e., the Left Arm and Club are traveling at the same RPM throughout the Downstroke (6-B-3-0).

If the Left Wrist is placed on the Grip in a Vertical Condition, then the Flat Left Wrist at Impact assures compliance with the 'in line' Left Arm and Shaft requirement. It also affords a visual confirmation of that compliance (4-D-1).

However, if you have Turned your Left Wrist when taking the Grip, then that precise amount of Wrist Turn becomes Wrist Bend at Impact. Hence, you have lost the visual check afforded by the Flat Left Wrist. However, as long as the Clubshaft has not passed the in-line condition with the Left Arm, you have complied with the Law of the Flail (2-K-#2) and maintained Rhythm. This compliance -- despite its lack of a visual check -- is known as the Geometric Flat Left Wrist.