A vertical punch means that the knuckles are aligned vertically with the body (parallel). This also helps keeps the punch straight. But most other punches from boxing or martial arts are horizontal to the body (perpendicular).
“The best self defense is to be invisible. If you cannot be, learn Wing Chun.” — Sigong Wong Shun Leung
Some Advantages Of The Wing Chun Punch:
Before getting to the tips for improving your straight punch and making it more natural and powerful let’s touch on some of its benefits.
"The best self defense is to be invisible. If you cannot be, learn Wing Chun." — Sigong Wong Shun Leung
The near invisibility (actually it looks more like a blur rather than invisible) is accomplished by a number of factors that all work together.
Simple geometry helps keeps the straight punch invisible. The shortest distance between two points is a straight line. This “shortest distance” therefore allows the fastest travel. It starts in front of you, at the center, and follows a straight and short path to the target. (In Wing Chun this straight path is called the “Center Line”.) Plus, the short distance the punch travels requires you to stand close to your opponent. Being close also makes it difficult for your opponent to see your strike coming. Don’t wind up to throw the Wing Chun punch. Winding up telegraphs (gives away the fact) that you’re preparing to throw a punch.
In simple terms this Wing Chun concept means flexibility and flow. An attack can turn into a retreat or a counter-attack... a punch can turn into a block, in an instant, in mid-flight - all before you complete the initial move.
The Wing Chun punch is most likely the first way you learn to apply the concept of interruptability.
The Roll Punch and Cover Punch (Trapping)
Throw two or more Wing Chun punches in rapid succession and you now have the roll punch (also known as the chain punch). As the first punch begins to retreat from its attack the second punch has already landed its attack. It’s like getting hit with a machine gun.
From the roll punch you learn the cover punch. Which means you’re blocking, or covering, one of the opponents arms while you’re striking (doing so limits the opponent’s options to counter-attack, allows you to control the balance, and gives you chi sao benefits). Like the roll punch, you continue to alternate the covering and striking hands until the opponent is out of the game.
These skills are made possible because of interruptibility.