Shigefusa 270mm kasumi yanagiba with custom, by me, desert ironwood handle

7 Feb 2011

Honyaki sharpening - The JNAT "dream team"

True honyaki blades are indeed a special breed of knife. Very often they are hardened beyond practicality making them a true menace to maintain. However laborous these blades may be to keep sharp, I have come to love them unconditionally. I don't know whether it is the myth behind them, the excellent craftmanship, the excellent performance or the sheer beauty of these knives that has won me over. Probably it is a combination of all these factors. The fact that I just love to sharpen my knives probably helps a lot too. These are the honyakis to be sharpened in this test. From the top, a Kasahara Shiroko #2 honyaki 300mm yanagiba and three Aoko #1 honyaki knives from Jyunichi Takagi.

The honyaki blades used in this test of Japanese waterstones
In this excercise I have experiemented with some of the Japanese waterstones that are said to be best suited for sharpening honyaki blades. Based on my experiments I have found the stones that I find best for the task of getting my honyaki blades up to exceptional sharpness and to get that totally scratchless almost sand blasted surface on the bladeroad of my yanagiba. From the bottom of the below picture we have a #1500 grit White Aluminum oxide ceramic stone called a WA stone from Iida tools, then a #5-6000 grit WA ceramic and then I switch to Japanese naturals.

In the middle to the left is my large Aoto from Iida tools, and to the right an Aizu stone from Maxim at Japanesenaturalstones. Both stones are truly remarkable medium sharpeners. Second from the top to the left is a Takashima Myokakudani from, a soft prepolisher with exceptionally even grit. To the right you see the characteristic red Nakayama Akapin from A very soft but agressive and yet very fine stone. This is my "rescue" stone when I get these hard to remove scratches from man made stones. On the top left we have the very soft and very fine grit Hakka. A legendary finishing stone for honyaki. Also brought to me by Maxim at, and finally on the top right, an Oohira from Maxim also. The Oohira is what I believe to be a tomae; medium soft, fine grit, and I included it for comparison to the Hakka.

The candidates for the honyaki sharpening "dream team"
My trading agent in Japan told me that he always starts out with a special kind of synthetic stone to do the ground work on the blades. A #1500 grit White Aluminum oxide stone called a "WA" stone. The aluminum oxide is some of the hardest abrasives in man made stones except for diamond. The abrasive in this stone is very densly packed and leaves a very consistent scratch pattern. It is a very efficient and hard stone and it will easily correct any issues with the blade road and flatten the back side perfectly. It is very important to resolve all issues in this stage to be able to get a perfect result in the end. As you can see from the below pictures, the WA (White Aluminum oxide) stone is very agressive even on these very hard steels, making it perfect to do the ground work on the blades.
WA #1500 on Shiroko #2 honyaki

WA #1500 on Aoko #1 honyaki

WA #1500 scratch pattern on Shiroko #2 honyaki
After this successful start I decided to apply the #6000 WA to erase the scratches from the #1500 WA stone. This finer stone actually caused more issues than it solved, so I left it out alltogether. Maybe a softer man made stone of finer grit would have performed better, but I did not go further on this and decided to switch directly to the Japanese natural stones after the #1500 WA.

Next up was the natural medium sharpeners. The Aoto and the Aizu. Both rated #2000-5000. I did not know which was the finer of the two, so I briefly tried both, and found that tha Aizu was both harder and a bit coarser than the Aoto, thus I began with the Aizu. This beautiful white stone with its olive green dots is a wonderful performer on hard steels and removed the scratches made by the #1500 WA with ease, leaving a dense and fine scratch pattern. 

The Aizu is a fairly hard and agressive stone

Aizu leaving a very nice and homogenous scratch pattern
 After the Aizu I could probably have skipped the Aoto alltogether and moved straight on to the Takashima. However, I wanted to compare the Aoto to the Aizu to place them individually in my setup for future reference. The Aoto proved to be everything I had hoped for. Most Aoto stones available today are of mediocre quality and would not be suited for sharpening the hard steels of the honyaki. This was not the matter with my Aoto from Iida tools. It proved to be a wonderful performer even on honyaki, both white and blue steel. The scratch pattern proved to be even finer than from the Aizu, producing the perfect basis for the Takashima.

The Aoto making a dense very fine slurry

The finish from the Aoto leaving not much to be wanted

Very happy about the progress so far, i moved on to the prepolisher. The Takashima Myokakudani. It is a beautiful stone with a very similar look to a Nakayama kiita, but with a more "sandy" look to it. The Takashima has a very homogenous structure with a very low content of unwanted particles leaving a very fine and exceptionally "clean" finish.
The Takashima Myokakudani
Closeup of the Takashima

The Takashima makes a very dense and creamy slurry
Closeup of the Takashima finish

I was very happy to see that everything was going the right way. The blade road on my yanagi slowly turned into that magically hazy finish. The edges on all my honyakis were pretty scary sharp allready, and I still had two more rocks to go.

Next in line was the legendary Hakka. A very rare stone hard to come by these days. Maxim at occasionally manages to source these beauties. I don't know how, and I really don't need to know as long as he keeps on scoring the good stuff and resell it at very reasonable prices.
The Hakka is a pleasure to use. It is fairly plain looking at first eyesight, but if you look closer you will notice beautiful renge or lotus scattered throughout the stone. The surface feels very smooth and even, almost like cool silk to the touch.

The Hakka quickly gives up a very dense and creamy slurry that "floats" the blade. After a while the slurry dries in to a fine clay that gives the legendary hazy, almost sandblasted finish.

Hakka stone, deceptively plain looking

Hakka closeup.  Notice the red scattered renge

Hakka slurry is almost like fine clay

Hakka silky finish

Hakka finish
After finishing with the Hakka, I tried the Oohira from Maxim I mentioned earlier in this post to see if I could do even better. This Oohira is a very fine stone of very good quality and it has proven to be exceptional on both carbon steels as well as stainless steels. However, the Oohira had some renegade particles that left light but still visible scratches on the now very silky surface of my yanagiba. I thus had to refinish the bladeroad with the Hakka to regain the abolutely flawless finish. 
 So no matter how good this Oohira performs on other steels, It is not the perfect finisher for my honyaki yanagiba and did not make the dream team.

A very high quality Oohira from Maxim

Oohira finish on the Hakka finished bladeroad.
Note the very fine but visible scratches

To sum up this rather time consuming excersise, I have found my honyaki "dream team". The #1500 WA, the Aizu followed by the Aoto and the Takashima finally followed by the Hakka. I could probably do with either the Aizu or the Aoto, but they really filled in each other in a way that makes it hard for me to separate them from my setup. I did not find the need for the Nakayama Aka-pin this time although it could probably be used successfully at some point in the process. However the point was to find the smallest setup of man made and natural stones to finish a honyaki to perfection. The perfect range for a perfect finish. I believe the team picture below is my "dream team" for this specific task.

So, what about the edges?  The sharpest I have experienced on any of my knives. Ever! Especially the Aoko #1's really got exceedingly sharp. My gyuto finally got that magical Shigefusa feeling to it, just sliding through everything I cut. The Shiroko #2 yanagi got that stickyness to the edge that shushi chefs speak so highly about. Sliding my nail along the edge very carefully makes the knife "stick" to it.
My personal honyaki dream team of Japanese waterstones
Hope you have enjoyed reading as much as I enjoyed sharpening. Thank you for your interest.


Sources to score the good stuff:
Hakka stone, Aizu stone, Oohira stone :
#1500 WA stone, Aoto stone, Shiro #2 honyaki yanagi: Iida tools Japan
Takashima stone: Aframes Tokyo
Aoko #1 honyaki knives: Japan woodworker
Nakayama Aka-pin stone: 330mate