A trader who is right sixty per cent of the time, but whose winners are the same size as their losers, makes barely enough to cover transaction costs. A trader who is right thirty per cent of the time, but whose winners are three times their losers, ends the year ahead.[a]
The second trader trusts asymmetry instead of frequency — and that is harder, because being wrong seven times out of ten is psychologically uncomfortable, even when the maths are working.
The system that follows is built around that single observation. Its purpose is not to win more often than the market — it is to make sure that when it wins, it wins more than it loses when it's wrong, and that the difference is reliable enough across regimes to survive a bad month.