t you need to be singlemindedly insane on trying to improve.
It's a real question, in my mind, as to what represents single-minded insanity
: focusing exhaustively and perseveringly on the sort of body-skill tanren discussed in depth on this forum over the past couple of years . . . or continuing with the prevailing training paradigm that yields rather lesser results despite years and thousands of hours of repeating the same tame thing.
One other point to note (again) about the new authorized translationL if I understood Nathan Scott correctly, there is new material in it that was not in the previous Japanese-language edition (from 1995). Again, the new material is anecdote and opinion, not how-to . . . but some may draw inspiration from it. And in any event the indispensable factor of hands-on training in the type of skills that Sagawa talks about make it foolish to look to any book for technical progress in his methods of training.