I have tried to read all the posts here on pinching and perhaps I missed this.  If I did, sorry for asking the question.

So if I understand this method correctly, one should pinch the bud at approximately 6 leaves.  Should this be done on cuttings that have been transplanted to a 1-gallon nursery pot and have grown to have 6 leaves?  Or is pinching done on inground trees or maybe even trees in 3-gallon pots?

You'll get different answers from different people.  I'd let my main stem grow to at least 2 1/2 feet before I pinched it if you want an upright form.  I often let it go to 4 feet.  Espalier is different.  I'd pinch the shoots off the main stem to 6-10 leaves. 

let it grow couple of years and when you are ready to have your tree put on figs, start pinching. some trees don't really need pinching, but i also heard that it's good for shaping your trees.

This sounds very simple but I sure would like to see a video demo.

To give you an idea on a fig tree several years old and up i pinch the ends mostly at 5-7 leaves and keep pinching any new shoots that appear on that same pinched branch to stop the vegetative growth on that branch and ensure ripe figs before season ends here in colder zone.
I may leave a shoot depending on the angle of growth and how i want to further the shaping of tree and its branching habit.

This is the same technique used in growing bonsai trees for shaping and to encourage new growth to bud out from lower on the branch.  With figs. new growth = more figs!

I would let small plants like that grow. Pinching is used for fruit production - or more accurately to quicken the ripening process of the fruit by limiting the amount of fruit set and directing the energy to the smaller fruit load. This is done on a well established tree, not of newly rooted plants or small plants.

I was reading at a Brazilian literature, and Jon is correct, such method is used to space out production and to slow down ripening of 5 year old established plants

My oldest trees are 4 years old, and I wish I would have pruned harder and not pinched so much!  You can't believe how many tiny little green cuttings I'll need to prune this winter due to my aggressive pinching practices.  I'm almost embarrassed to send those small cuttings, but I will!  Along with some big ones from the branch from which they grew.

I did get a branched cutting from a member here, so I cut that 2" baby off, and amazingly, it rooted, the sweet little thing!  Waay before the bigger cutting rooted.  Now they have all rooted, and I have this darling little extra.  Just checked on it!  It's alive and happy!

Merry Christmas Eve everyone!

Suzi

Suzi, I got some tinny tinny cuttings and they root just fine. I have a very special Black Greek that the cutting was like one 1/6th of a pencil.

Pinching should only be done on established plants.

But from my observations, pruning of all side branches should be done to promote the growth of the main stem (trunk) for young plants. The limited energy of the plant will be directed into the main trunk. Factors such as Zone, container or in ground will decide the final pruning and pinching done on the tree.

Attached are diagrams for pruning techniques found on this website, If you search for "Japanese fig espalier" you will find lots of pictures and detailed explanations posted. Note the 1st step of pruning, the tops can be air layered for additional trees. Also I have been able to do the 1st and 2nd steps (of the tree/container form) in one short season. Bob C's answer in post #2 would also apply here, I have gotten 4 feet of growth from cuttings this past season (while maintaining a single main trunk).

Container or Tree Form.

Espalier or Step Over Form.