You know when you watch, say a kung-fu film for example.
The star punches the villain - and we cut as his fist meets his face - and then we begin the next cut a few micro-seconds before, just before his fist made contact with his face.
We do this so that our brain has time to readjust to the new shot, and then pickup where we left off, I understand that, but what is it called?
Could we call the extra second on the second cut, pre-roll? Or is that specifically for the bars and tones that roll prior to tvc etc.
Yash, a mentor of mine many years ago called that the “Hollywood triple-cut” - triple since it was common to edit three angles together of a crucial moment such as an explosion. I’m not aware of any universally accepted term though. If you walk into an edit bay and request that something be “double cut” or “triple cut” or even “stutter cut” the editor will probably understand what you want. But really it’s just a very common trick that editors use without discussing much.
The purpose, as you guessed, is that with an action that happens very quickly such as an explosion, the action is shown from multiple angles, with each successive edit starting a few frames earlier than where the action would be in its “real life” progress. In other words, each edit is repeating a couple frames. The number of frames repeated depends on the speed of the action and personal taste.
Done right, this is experienced by the viewer as closer to true continuity than without the slight repeats. Once you’re wise to the gimmick, you will notice it used all over the place. Older action films were notorious for pushing the reasonable limits of this technique.