Traditionally sword polishers and the most accomplished Japanese knife sharpeners have always preferred natural waterstones. But the best natural waterstones come from age-old quarries that are largely exhausted. Naniwa has always strived for their artificial waterstones to have a very natural feel, and their Chosera stones are their top-of-the line stones. These are the best, fastest cutting waterstones we have ever seen. However what really attracted us to the stones is the feel of the stone on the steel as you sharpen. You get a firm, consistent feel, with no slipping, glazing, skidding, and a good sense of feedback on how the stone is working. We would be the first to admit that they are really too expensive for the casual sharpener, so we don’t recommend the stones for beginners. High end knife sharpeners, on the other hand, will love these stones. The high cost is a function of the stones’ size, the large amount of abrasive in the stones, the way the stones are manufactured with a magnesia binder, and how the stones are conditioned after manufacture to keep them stable.
At our request, the factory is packaging these stones without bases to that they will fit in any existing sharpening jig you use, and so that you can easily use the both sides and the edge of the stone. We also think the stone will soak more evenly, and, more importantly, dry better. It is very important that the stones be soaked for 15 minutes before use, and after use, be kept away from heat and sunlight so that they dry evenly. If they’re not allowed to dry slowly, the stone may develop minor cracks in the surface. The stones come with Nagura stones - used to work up a slurry and for flattening.
The Chosera stones come in six grits: 400,1000,2000, 3000,5000, and 10K. . 8 1/4" x 2 3/4" (210 mm x 70 mm) and 1" (25 mm) thick. The 10k stone is 1 1/4" (30mm) thick. These are big thick stones which will last a long, long time. All the stones, even the coarser grits perform very fast and are noticeably harder than other stones on the market. The 10K in particular is really something special. Every person we know who has tried the 10K stone has unequivocally called it the finest artificial water stone they have ever used. It’s a true pleasure. In Japan the 10K is marketed mostly to sword sharpeners and comes wrapped in a cardboard presentation box.
While we wax euphoric about the 10K we don’t want people to ignore the coarser grits. The 400 is a great coarse stone, very fast cutting without being uncomfortably soft. The 1000 is our favorite workhorse now - cutting fast without the coarseness associated with a rougher stone. Many people sharpen knives up to 5000 and I think you will find the Chosera 5000 an impressive finishing stone, which while overshadowed by the 10K is still a standout in its own right.
We understand these stones are not for everyone. But if you’re looking for the finest artificial waterstones available on the market today, you will not be disappointed. Made in Japan.