A dull knife is the one that cuts you. It skates off what you are cutting instead of biting, and your hand is usually where it ends up.

This is a pocket stone in a protective case — the kind you actually carry rather than the bench stone sitting at home. A few passes brings back a working edge on a camp knife, an axe, or a machete that has been through too much dry wood.

Keep it with the knife, not in the toolbox. An edge gets touched up when the stone is within reach and never when it is not.