That depends on the type of martial art. As far as I know, jiujitsu mostly focuses on grappling and throwing and is practiced in pairs where people alternate between performing a technique and having it performed on them by their partner. This should be far more difficult to screw up than a striking art in which you can create the illusion of learning by having people strike at the air repeatedly.
How to tell a martial art (e.g. art used for making war in the old days) from a “martial” art (e.g. a version of soccer one drives the kids to two times a week): it doesn’t award belts.
As martial artists have pointed out for a long time, holding a black belt is a fairly weak predictor of success in a true fight.
That depends on the type of martial art. As far as I know, jiujitsu mostly focuses on grappling and throwing and is practiced in pairs where people alternate between performing a technique and having it performed on them by their partner. This should be far more difficult to screw up than a striking art in which you can create the illusion of learning by having people strike at the air repeatedly.
How to tell a martial art (e.g. art used for making war in the old days) from a “martial” art (e.g. a version of soccer one drives the kids to two times a week): it doesn’t award belts.