The most often? What fighters consistently knocked guys out to the point where you could count to 50, or a 100? Marciano did this several times. Who else?
Marciano was the first to enter my mind. When Julian Jackson landed flush, the lights seemed to go out.
Patterson Ingo II. Louis vs Braddock, and lots of other people. Marciano Walcott, Layne. Robinson Fullmer II
Sonny Liston-Albert Westphal- dropped like he been shot Ezzard Charles-Bob Satterfield Jersey Joe Walcott-Ezzard Charles III- Charles did not know where he was, it was like he had brain damage for 5 min after the fight was over Julian Jackson-Herold Graham Cleveland Williams-Jim Wiley- Wiley got to his knees at 10, starting crying then fall back flat on his face, while his ******* cornerman took like a good 30 seconds to enter the ring and help the poor *******. A double left hook combination 33 seconds into the first round by Williams. Henry Cooper-Joe Erksine III??? the fight where erksine lay dead hangin on the ropes looking like a corpse
It's rotation of the cranium that causes this type of coma.Marciano got incredible torque into his punches.In this aspect of his punching technique,he was as great as Louis. Add Bob Foster, Ray Robinson
John L Sullivan frequently sparked people for 20 or 30 minutes with those skin tight gloves. Sam Langford could separate a man from is senses so cleany that he never knew what hit him and generaly did.
I'll also nominate Tommy Hearns. David Tua had a few like this as well. Michael Moorer and John Ruiz come to mind.