Go uses a very elegant handicap system of spotting stones. The weaker player essentially takes between 1 and 9 scripted moves before the actual game begins. It

Go uses a very elegant handicap system of spotting stones. The weaker player essentially takes between 1 and 9 scripted moves before the actual game begins. It's an excellent system for several reasons. Most obviously, it largely preserves the flow of a "normal" game, whereas something like handicapped chess has completely different opening play. But another major benefit is that it remains a good way to practice for equally-skilled play. The skills used to overcome or capitalize on a handicap transfer effectively to playing out a weak or strong position in a neutral match. There are relatively few handicap-specific strategies to play, and "irrational" play is generally less rewarding in handicapped games than simply mismatched ones. (I doubt this applies in martial arts, but in many games a heavily-outmatched player is actually rewarded for bad play. If their odds of winning on performance are bad enough, they'll succeed more often by making surprising or high-variance moves and hoping for an error. There's an excellent story from DF Wallace about how as a teen he won local tennis tournaments by simply playing safe and waiting for unforced errors, but actually had less upward potential than the people he beat. When unforced errors became scarce, he had no strong play to fall back on.) Interestingly, the handicap system could be extended beyond nine stones without losing too much elegance, but by tradition it isn't. It's understood that across any greater skill gap, it's essentially impossible to play a real and educational game. The weaker player won't be able to trace why a move is good or causes them to lose, and so handicapped games should be replaced with either direct lessons, or play tailored to education instead of competition. It sounds a lot like the situation in martial arts, and I suspect holds across a great many other games and competitions.