Old pines have plated bark. There is no good way to accelerate the development of bark. Sure, some have tried making wounds, hitting the trunk with a hammer, wiring and letting the wire cut in, etc., but nothing looks like naturally aged bark.
Remember, too, that the pines we see in pictures from Japan have been in training for decades.
Japanese Black Pines are the "king" of bonsai. Everyone who does bonsai really ought to have at least one. They are easy to reduce needle length on, back bud easily, and respond very well to the proper techniques.
That said there is a LOT of misinformation floating around about how to train JBP.
John Naka's books are NOT a good source of JBP technique! Styling, yes. Technique, no. You see the technique of decandling JBP spring candles was unknown to John. He published his books before decandling became well known.
There are some who treat Naka's books as if the are the ultimate source of information. This view is shortsighted.
On this site, Brian Van Fleet shares an excellent tutorial on the modern JBP technique. It is a single at
www.nebaribonsai.com.
And, please don't think I'm a Naka hater! Au contraries! I took classes from John, own three of his books. My copy of Bonsai Techniques I was personally dedicated to me by John. John was always lo
Oking for new techniques, and it is unfortunate that Decandling was discovered and kept secret for a couple years right at the time John was writing jis hooks.