As cool as it is, its one of the least practical techniques I have ever seen.

A: Excuse me sir
B: Why is your hand so close to me?
(crunch)
A: Terribly sorry
B: OW!
Please note, although no boardcode and smiley buttons are shown, they are still useable

thats what makes proper wing chun so cool, most people dont under close range fighting and train to fight medium to long range. learn to fight and understand all 3 worlds my friend

I think the principle behind the strike is fine - ie generate power from short distance with no recoil.

For pre-emptive strikes in self defence this is important. For example practising generating power from having your hand on someone's shoulder to hitting them in the side of the neck or jaw. It is also good for looking at strikes from a stand up clinch range, where you have limited room and control.

I seen a couple of demonstrations with one inch puches, most of which were pushes. All have had similar things in common, the demonstrator taking their time to get into position, them visibly trying to relax their body beforehand. Perhaps this was part of the show for the audience, but unless you can hide this preparation, I don't see this as a workable fighting technique.

As other people have said if you're that close then there are other more reliable weapons you can rely on. This is probably why you don't see one inch punches like the one in clip in MMA or boxing.

It's a nice demonstration and definitely nicer than getting someone up and doing a full on cross to their face to show that that is an effective technique.

It is true that training very close quarters gives little room for openings when your trying to cover yourself from stikes, knees etc and looking for that opening. The general idea of the OIP is to hit the opponent with a short quick movement into the sternum or ribs for example to eith stun or drop the opponent.
If your aware enough when you execute this forceful strike you can act on the stun, balance loss or possibly the person dropping to the floor.
As Steve Rowe said people react differently, and the react differently still if they don't expect it hence created your window of opportunity.

In WT we use body mechanics to produce force from any distance. Because WT is very up close and personal you have to produce a lot in a short distance.

In class the other day we had our arm straight, fist on opponents chest and were using body mechanics to push them back forcefully. No pulling back and pistoning or shoving. No extention of the arm or shoulder.

Bruce Lee's one inch punch was always quite showy but then he was in showbusiness. WOAHHHHAAAAAAAAAAAAAAAAA

I agree. Bruce Lee demonstrated the one inch punch for the purpose to show that prowess does not have to come from the back up from a persons weight, but also flexion. The art of flexion is the opposite of strength. And contributes to the "just do" principle. The just do principle does not embrace techniques. It is an advanced level. Most of all it is not just a particular stance flexion is generated from. Look at what Bruce Lee did with his lower torso before the one inch punch was applied. A powerful flex can be achieved with your kicks as well contributing strength to tendons and muscles for longevity as we age.