The I.O. Shen Mastergrade 120 and 320 Dual Grit Whetstone is a classic way to keep your knives razor sharp. Even the sharpest and most expensive blades will loose their edge over time and a sharp blade is more efficient, takes less effort to use and is safer as there is less likelihood of the blade slipping when in use The coarse combination of this whetstone is suitable for removing chips and nicks from blades. The I.O. Shen Mastergrade Dual Grit Whetstone is a simple and effective method of keeping your knives in tip-top condition. Soak the whetstone in water for approximately 20 minutes before use. Place the whetstone back in its tray, coarse side up, allowing any excess water to drain off. Take your knife and smoothly run the blade in a sweeping motion over the length of the whetstone making sure you keep the blade at an angle of approximately 20° to the whetstone. Ensure that each sweep takes in the whole length of the blade - from heel to tip. Repeat this process several times then turn the knife around to work on the opposite side of the blade. This process brings back the fine edge to the blade. Repeat the same process using the fine side of the whetstone to give the blade its razor sharp edge back. After sharpening always carefully handwash the knife and dry immediately with a tea towel.