The thumbnail test (not recommended for novices) - With this test you take your newly sharpened blade and run it oh-so-delicately over your thumbnail. If you feel it digging in even a tiny bit, it’s likely sharp enough. If on the other hand it just slips and slides across the surface of your nail it’s not sharp yet. Again, this test is only recommended for people with lots of experience handling knives and even then they’d probably be better off just grabbing a tomato or a piece of paper.
I'm a novice knife sharpener. I've had to unlearn what my grandpa taught me in order to use these. So far, I've had decent but mixed results. I've switched to my cheap 200/400-ish cheap tool stone from harbor freight for cutting a bevel when the blade has either been damaged or did not have a proper bevel. The 400/1000 grit stone in this kit is soft. Very soft. I have bowled it out several times. It makes keeping a steady angle difficult. But these stones at this price point are meant for learning, and for that they serve their purpose.
Naniwa also makes the Naniwa Traditional line of stones, these are less expensive than the Professional lineup and I believe were created to compete in terms of cost with some other brands such as King that are less expensive, more attractive to some who are just starting and may not want to invest a lot of money. I have tried the Naniwa Traditional 220, 1,000 and 2,000 grit stones and I thoroughly enjoyed them, so if you are considering a less expensive brand to get started, these are also good. I do not like them as much as the Professional line but I do like them, they work, they make the knives sharp.
Let’s start with Arkansas. If you have heard about Arkansas oilstone, it uses the Novaculite stone that mined in Arkansas. The most expensive of Arkansas stone is the Hard Translucent model that begins to rare in the market. If you want to shop for Arkansas, they are available in different grade starting from Soft Arkansas, Hard Arkansas, Hard Black Arkansas and Hard Translucent Arkansas. The finest grade of Arkansas can shape such of mirror polishing edges.