Nothing, same rules, they just teach it with a different stance.
When you see boxers leaving their left arm down as a long range weapon, the "dutch" style stance is the same as that, but with the leg instead. You put %80 weight on the back leg and you like hover your left leg up and down. It's like a jab but using your leg.
If I'm correct, the hands are different too. Instead of tucking your elbows into your body and putting your hands by your temple, your turn your forearms outwards as if you were blocking a jab.
Here is Ernesto Hoost in a Dutch Stance
