I sowed those Japanese Black Pines 5 or 6 years ago. I am not in a hurry and did not push their growth using large pots or overfertilization. What they do not show in caliber, they bear in character and ramification.
I added movement to the trunk lines. Some are tortuous while others will become literati. I tried to not repeat the same curves using my hands on the wire, but it is hard to navigate against our own inner nature.