The Japanese do it differently than we do. The hobby growers there will start several dozen if not hundreds of cuttings, grow them for a year or two, then cull them to pick 5 or 6 to work with in the future. Rather than try to take one tree and micromanage it to perfection, they let nature do the work. Once they have a manageable number to apply techniques to, then they get to work using good starter stock.