if you had only one tech to teach for self defence, which one would it be?

if you had only one tech to teach for self defence, which one would it be?



Let's put it this way: say your little sister is going on gap year trip and all of a sudden you realise you won't be here to help her if anything happens. Still you'd like to teach her some techniques for self defence purpose.



The problem is you just have time for one tech (not the full system). So which one would you choose?