How long did the boxing match between Ralph Walton and Al Couture last?

Just 10.5 seconds.
Ralph Walton was knocked out in ten and a half seconds in a bout at Lewinston, Maine, USA, on 29 September 1946. It happened when Al Couture struck him as he was still adjusting his gum shield in his corner. When the bell rang, Couture dashed across the ring The ten and a half seconds includes ten while he was counted out

That sounds a little irregular. Most sets of boxing rules require the ring to be at least 16 feet square, so the distance from corner to corner will be just over 7½ yards. If the winner got from corner to corner in half a second, he must have been moving at 15 yards a second or more than 30 miles an hour, which is faster than any professional sprinter can manage, even today. Something tells me that Couture must have been a long way out of his corner when the fight started.

Or there could have been a quick count. 1,2,3,4,5 And 5 is 10. ha ha

Yes, sequoianoir, right on! -- TabbyTom, The Best,Worst, and Unusual, by Bruce Felton, and Mark Fowler. Galahad Books, New York. Page 356. -- bluegill, -- could have been a quick count. Not sure if the ref's in that time were very honest, huh?