http://outdoors-magazine.com/spip.php?article341

It's about a Mors 'inspired' knife made in Montana (nice knife actually) but quotes the section of Mors' book on knife selection.

Originally Posted By: p109-111 Northern Bushcraft

As a test of strength, a good knife should not break when driven four centimeters into a standing tree at right-angles to the grain, and the handle bears your weight as you stand on it.


Now that I read this (I lost my copy of Northern Bushcraft ages ago) I'm tempted to try it with some of my questionable knives just to see.

The book also mentions a full tang with a pommel which is strong enough to allow the knife to be driven into wood tip first.