Have a look at my posting on "show us your staff weapons" 6th Nov 2010. I posted on 22nd Nov. That is an original "Short Jeddart Axe" circa 1480 - 1520, the woodwork is also original which is rare. the blade is 26 inches, and capable of just that sort of damage. This is a similar blade proportion. Used from horseback who knows ? I can't see why not. Did the japanese not use the nagamaki either side of the horses head?
I presume since this is the short version. (Buccleuch is recorded as equipping his men with them in 1596, Calendar of Border Papers), that in that case there was also a long version. I have only ever seen three of these, there may be a fourth which was allegedly found in the moat of the keep at Newcastle upon Tyne, but no-one in the Museums Service down there can find it any longer, and I suspect that it may be identical with one of the three that I know of.
I published on this in a little book entitled Death, Resurrection and the Sword, which lists the previous opinions and confusions over the Jeddart Axe / Staff, and there have been a few!
Brian Moffatt