The fake tricks your opponent into going the wrong way, the feint in taking too seriously or not seriously enough the danger, the foil nullifies and confuses an opponent physically and mentally, the draw offers oneself as a target, the final focus strategy tricks an opponent into focusing within.
Self-doubt is often down to a lack of confidence and many competitors compete to overcome self-doubt or feelings of a lack of self-worth. In combat if one can destroy an opponent’s confidence you can win before he even steps onto the tournament floor. When a fighter doubts that he can win he is often already beaten for instance if you are novice fighter and you step onto the mat against someone you know is a world champion then immediately you experience feelings of self-doubt.
As a strategist using the stratagem of doubt you must convince your opponent that it’s no use trying because he can’t win. This can be by getting into his head before the fight to undermine his confidence 'psyching him out' or getting your team to do so.
If the fighter doesn’t know you, you can get your team to befriend him and tell him stories such as ‘he hasn’t lost a fight in the last four years’ or the last guy he fought isn’t out of hospital yet. They can be pretty cheap tricks but if you goal is to win then you might employ them.
In the film ‘Pumping Iron’ many years ago you can see a young Arnold Schwarzenegger is seen psyching out the huge Lou Ferrigno undermining the confidence of Ferrigno as a relative new comer to the big leagues where Arnie had been for many years. Did it work? Well Arnie won. Was it worth it? Who knows but if you want to be a master of strategy you must consider how far you will go in order to get what you want.