all in the wrist

[azyousual]

Could you explain this idiom: all in the wrist?
Let me give a few examples (I found them on the internet):

Good bowing is all in the wrist and staying loose and relaxed. If you feel any cramping, you are gripping too hard.
Making crepes, like making many things, is all in the wrist and the fingers.
Some say the answer to success in fishing is all in the wrist, but I really think it is all in the heart.

[Clare James]

Not exactly an idiom - more of a collocation - a commonly used collection of words together. It just means that the success of the activity (fishing, cooking or sport) is due to the movement of the wrist.

[MrPedantic]

As a footnote:

In contexts such as this, "to be all in the X" means "to reside wholly in the X". ("All" is an adverb here.)

Thus the first sentence might be rephrased as:

1. [The knack of] Good bowing [resides wholly] in the wrist and [in] staying loose and relaxed.

(Welcome to Using English, Az and Clare, by the way!)

Best wishes,

MrP