Finess Testing of a Japanese Natural

I've been thinking for a while about posting my testing method for razor-worthiness of a Japanese natural hone. Mostly this is about fineness and the quality of the edge. Speed is secondary although in general a fast stone is preferable to a slow one.

The first thing that I have to do is define what I'm testing for. What I want, and usually don't get, is a super-smooth shaving edge that leaves BBS/dolphin smooth skin. This edge will feel like you are shaving with a butterknife, not a razor. Stefan (@mainaman) posted an excellent summary here:

https://straightrazorpalace.com/honi...ing-stone.html

It's worth re-reading his post as an introduction to this one. I'm going to try to add a little detail to how I know that I have one of those exceptional stones during the honing and testing process. Of course, you could just start throwing razors at the stone, but where's the fun in that?

I use HHT to test during this progess, but which test you use isn't important, just that you understand how to interpret what the test is telling you. A tomonagura that is known to be exceptional and not 'knock down' the edge when used with other known fine finishing jnats is necessary. My normal progression is Shapton Pro 2k (the normal bevel setter), Shapton Pro 5k and 8k, koma nagura and tomonagura on the finisher. I honed for a couple of years without the 8k and I can't tell the difference in the end result, but 8k striae may be a little less stressful with a slower finisher than 5k, but the koma should get 5k striae in shape to finish.

Image below of the stone that I'm testing and my razor progression. First off is a Gold Dollar. I use one that's hand picked for lack of the usual defects and to keep wear off better razors. If the stone's a dud, no point in using a pristine Iwasaki tamehagane to find that out. Or even a nice mellow English or German user razor. The GD also seems a little more sensitive to hone quality than a 'normal' razor. If I get excellent HHT root-in or -out, that's what I'm looking for, silent HHT is ideal.

Next up is a 'normal' carbon steel razor, in this case a Hayashi 1000 user-grade razor. There's not much special about it, it hones normally and it is known to be able to take a fine edge. Most any razor would do here as long as it can take the finest edge. I would expect the HHT to be better than the Gold Dollar with the same honing technique. If the edge tests and shaves well, then up next is a Filly 14.

The Filly 14 is ground very thinly at the edge and is of course a singing razor. I think any 'singer' would do here. What I'm looking for is silent HHT root-in or -out. Because the edge is so thin, it takes a pretty good stone to make an edge that the HHT won't 'ping'. If I get this result, I'm encouraged! It's what I want.

The acid test is a Puma Inox Frozen Steel, and this razor has always been difficult for me to get the same edge as a carbon steel razor. I like to use it because you have to know if the stone works on all steels and grinds. Like the Filly, it is also very thinly ground and difficult to get that silent HHT. If the results are that butterknife edge, at this point I can be sure that I have a truly top-tier jnat razor finisher. I've never had exceptional results off the Filly and Puma and had the stone fail on any other razor unless there was something wrong with the razor.

In the image below, I am up to the Puma so wish me luck! The stone has passed with flying colors so far. It's one of 3 stones that I bought, the other 2 are nothing special so you can get an idea of what acquiring a special jnat really costs.

Hope this helps!

Cheers, Steve

Great topic as I have been thinking of the same thing lately. Two thumbs way up!