Diamond plates are the best way to keep your scandinavian knife sharp. They're small, lightweight, portable, never seem to wear out, and are the perfect size and weight to easily to run over the blade, as opposed to a larger stone where you have to run the blade over the stone. This is a great hand-held diamond sharpener from Mora, with a medium-fine grit around 600. It's just under 6 inches long and is very lightweight at only 0.6 ounces, so you can use it for a long time without your hand or wrist becoming fatigued. Comes with a simple plastic sleeve.