I got a garden knife some years (10?) ago and it was the sharpest I
had ever used -like cut glass. .
It was serrated and it would cut through small branches like butter
(we used them for pruning young trees)
The downside was it was really brittle and if you were tempted to
push it instead of drawing it towards you it would snap.
Would that have been a carbon steel blade?
Where could I order them from (I don't seem to have much joy in
googling *carbon steel blade* so maybe it is some other manufacturing
method.....