Juniper Twisted trunks

Student asked Sensei Boon on how to develop the twisted trunk of most juniper bonsai:

These trees are field grown.
They start as young whip probably about 20-30 cm long
Twisted and bend in winter.
After a year, it is transferred into the field.
About Juniper, the height will be the same. It is not the tree that will be cut down to grow new top. So whatever size you want, you will have to plan for it.
You cannot start this with old stock because you cannot twist and bend, like young materials.”

Bonsai Tonight

Shimpaku junipers should invest in trunk development
Small whip development — add twists. More important than bends, include complex life lines with twists. Twisting cambium up to pencil size. After that the twists are more gradual.
Ideally trunks are not round, but ribbon-like. Getting it out of round as early as possible—depending on the size of tree you desire.
Japanese masters consider that loss of deadwood over time versus speed to develop a tree. Depends on the climate that affects/ accelerates wood decomposing.
[Jonas] Start carving about 5 years prior to your finished tree.
Developing fins: grow life lines on opposite sides and continue to scrape away the sides. The life lines will fatten up quicker than if round. If desiring a single life line, the outer life line is removed.
Recommend leaving the life line on the inside of the curve, adding mass more quickly and contrasting deadwood on the outer edge—the oldest wood, theoretically.
Avoid making all of the curves having the same radius, vary them with larger curves lower and tighter as the trunk or branches taper narrower—able to bend more tightly.
Consider that the wood fin will add over time. So the inner radius should not contact or be so tight as to make contact with itself before achieving the final girth.
Similar if starting three life lines, reducing later—but the degree of the final wood is less.