NaniwaStraightening Stone IO-1142 Grit 220

Leveled out my 5+ year old synthetic stone with this in a matter of minutes. Suddenly, my knives keep their edge about 4x longer than before! I'm a professional line cook, so those knives and that stone see a lot of action. I was also able to use the rough backside of this stone to put an edge on a hopelessly dull old pocket knife!

I have used a full sheet of 120 or 220 grit waterproof silicone carbide sandpaper on a piece of 12”x12” 1/2 inch plexiglass to flatten my water stones for 40+ years. Over all those years I’ve probably spent 50 times the cost of this Naniwa stone on silicone carbide sand paper.The sandpaper method works OK but it’s annoying for a bunch of reasons so I finally broke down and bought this Naniwa flattening stone.The Naniwa is faster than my old method, easier to use and store and the Naniwa leaves a nice finish on all my stones. The Atoma 140 diamond plate is the best tool for flattening but it’s expensive.My only “con” is that I wish it was about 25 % larger. Naniwa makes a bigger flattening stone but it’s about $70. If I need a stone that big, I’ll revert to my full sheet of silicone carbide sand paper and plexiglas.Attached is a photo of the Naniwa stone (black) next to my tan 50 year old King 6000 grit water stone. Hope that helps!

This product is intended for the maintenance of sharpening stones, so it may not be necessary for everyone.However, if you have purchased a Japanese whetstone, we highly recommend getting this as well.It is used to keep the surface of the whetstone flat and properly maintained.

I'm happy with my stone. I checked it with a leveler right out of the box. It's flat and works great.

I wanted to practice flattening my waterstone. So I started using the non-uniform side first. Big mistake. My stone was severely cupped after only 30 seconds or so. So I switched to the other side of this product (completely flat side) and was able to flatten the stone properly. This might work a little better if the stone being flattened has a shorter length than the corrector. My stones are a bit longer than this corrector and it seems like either this or my inexperience is causing a very slight concavity in the final stone. All that being said, this product works very well to get a nice even surface for sharpening!

Heavy Duty and Good quality stone. Don't use the cheap Amazon knockoff brands. I learned.

This stone did not come flat. I guess you have to buy two of them and face them on each other.EDIT: I am ordering a second of these stones. I am sure that for the price of a second stone this will be a FIVE STAR product.The finish it leaves on a 6k grit waterstone is very nice. Also, if you happen to like a crowned stone, the slight warp in this stone will give you a nice shallow crown.

A whetstone won't help if the surface isn't flat. This is perfect for knife enthusiasts who sharpen at home to ensure their whetstones are flat.