Hakka Renge Review

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Well-Known Member
Aug 25, 2011
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I decided to hold off on the synthetic stone reviews in lieu of a few reviews I consider to be more interesting.
I have also been persuaded to post where I purchase each stone. This allows those who may be new to J-nats or sharpening in general to have a reference for the product quality of different vendors.
Disclaimer: I have bought from multiple vendors in the past, not all of them well liked. Please keep the thread clean of any vendor scrutiny and or personal business with others. I would like to keep my stone threads about stones, and not about vendor bashing, thanks for your understanding and cooperation. With that being said…feel free to ask any questions or scrutinize each stone or apparent flaws in my technique to the maximum. This is how we all learn!!!

For this review I chose one of my latest purchases, a 4th Hakka. I chose not to do a Hakka shootout with all 4 (maybe later… and by that time 5 or 6…wife willing). I find that performing a single stone review allows me to be more complete about my findings.

I purchased this stone from Maksim at JNS.

Sadly, this Hakka sat on Maksim’s website for several weeks, begging to be bought. I feel bad for anyone who decided against it…for whatever reason. It has to be one of the most interesting Hakka specimens that I have come into contact with. I’m a sucker for the rare, so it called to me every time I perused!!!

First off, the presentation of this stone is simply amazing. It came packaged in a wooden box with burnt kanji, something I haven’t seen very often outside of presentation or gifted knives/weapons. The weight of the wood reminds me of balsa or basswood, but a quick discussion with Maksim, yielded a different story. Apparently this is a type of Japanese deciduous tree (akin to Oak). Either way, it’s a beautiful addition to the stone, and makes it a perfect mantle piece to go with my suita’s. I wish I had a box like this for all of my stones…or at least my showpieces.

Hakka Box

Hakka In Box


The stone itself is approximately 200x 76x 45mm. There is not a single inclusion in it whatsoever, and it is full of Renge patterns that go all the way through the stone. This trait in and of itself means I will never sell it, because anyone who has spent time with a hakka knows that inclusions (whether toxic or not) are usually part of the game. This is especially true for a stone this large. I have seen stones like this sell for 2/3x what this listed as.

Photos of Hakka Before Sharpening


About my testing procedures:

I performed two separate testing procedures on this stone: 1 speed test and 1 finish test.

For the Finish Test

I tried to start with as clean of a knife as possible. I started out with the
JNS1k>Binsui-do>Red Akapin (aoto)>Takashima Myokakudani.
This progression left an excellent 6k’ish finish with very dense and shallow scratches on the jigane, but also a very dull hagane. Please see a full list of conclusions at the bottom.

Moritaka Finished with Takashima

Hakka Mud on stone and moritaka



Final Hakka Finish

For the Speed Test
I worked my knife directly from the JNS 1k. I wanted to see how long it would take to refine the edge and finish to an acceptable level. Note: I did not really try and remove all of the scratches, but I was working toward a 95% scratch removal. And as can be seen in the finish, I apparently had a small amount of contamination on my 1k stone as there are some very deep scratches still present. Please see a full list of conclusions at the bottom.

Moritaka with JNS 1k finish (note: I used an older photo, but finish is always the same)

Final Finish from Hakka

I believe the pictures are more complete than my statements could ever produce. This particular Hakka is about the finest specimen I have seen. It isn’t as fast as some of my other Hakka stones, taking approximately 12 minutes to refine the 1k finish, but it produces a far better finish to both the jigane making a perfect sandblasted look and hagane making the start to a mirror polish. This effect is further amplified if you can correctly precede and follow this stone with other top quality J-nats. When I followed up with an atagoyama, the results were simply stunning, producing one of my best finishes to date.

So, what about the rest…the details everyone drools over. I’m not big into putting concrete grit ratings on natural stones, but I can say this stone sharpens as beautifully as it looks. A 45 second soak is more than enough to get you going, and only a minimal amount of water is necessary as you progress. You can tell this stone is hard, feeling almost like a slick glass to start, but within seconds it has begun producing mud which turns the stone into a silky smooth and almost buttery feel. If you aren’t careful, the mud quickly thickens on you and has a tendency to grab at the blade drawing it into the stone. This is not a bad feature, in fact quite the opposite, because it helps to produce an even finish across the blade road, but can be hazardous to your health if not paying attention (say if you wife is bitching at you for getting mud all over the kitchen counter while you are trying to sharpen for a review). A picture of the mud can be seen above. Taken approximately 3 minutes into sharpening, I was using medium to med/heavy pressure. If you will notice, the mud is a reddish brown color, with very little apparent swarf, quite misleading as it is refining both the finish and edge effectively.

It has excellent feedback and is also quite forgiving for anyone who hasn’t quite mastered the art of sharpening (cough, cough…me…me). About the only negative thing I can say about it, is that I hate I don’t have 2!!!

Some personal/anecdotal notes:

In my testing procedures, I attempt to be completely unbiased, presenting only my findings, while letting others produce their own opinions. However, I also would like to throw in some of my personal thoughts.
Overall, I would say this or just about any Hakka I own is a suitable finisher for honyaki blades. But, in reality, I never stop at the hakka. To me, it really shines as a pre-finisher, because it produces such an excellent finish to the jigane, but at the same time leaves a little to be desired in the polish of the hagane. I have never found a stone that could do both effectively while still being fast enough to erase synthetic 1k scratches in under 15min. In fact, this particular specimen has come the closest to filling that gap for me, which is why I advocate putting a hakka in the list of must have stones.

With that being said, I can’t advocate this being your only natural stone, especially if you intend to use it after a coarse stone or even a 1-2k synthetic. Although it is capable of refining the finish (as you saw earlier), 12 min on a single stone is unacceptable, putting far too much work and strain on a stone as expensive as this. It was produced as a finishing/pre-finishing stone and not as a workhorse sharpener. For instance, overall, it lost an average of .04mm start to finish when refining the 1k edge (measured at 10 points, with digital calipers). This may not seem like much, but it means that a stone, which is 40mm thick, would only last about 1,000 sharpening sessions before being completely used up. Remember, this also neglects any necessary flattening (which I generally average between .05 and .1mm stone loss). Assuming you sharpen once a week (Not likely), and flatten this stone 6 times per year, this means your stone will be used up in approximately 15 years. To those who see a stone, as a simple tool to achieve a goal, this may not seem like a big problem. But, for those of us who view these stones as a part of history, this 15 year mark takes on an entirely new meaning. A good alternative is to use synthetic stones that produce up to a 6k finish, then produce a natural stone finish with the hakka. It saves quite a lot of trouble ;). Or, you can go with my method and get lots of J-nats, both coarse and fine, and have fun the rest of your life!!! The choice is yours…

I’m not very big into videos, as I can barely get my photographs to look correctly when posted, and I don’t have a video camera, which also makes it a little tough to get good video. But, I wanted to talk a little about the edge this stone produces. It is most definitely wicked, almost razor like, but not nearly as slick. It will bite a tomato with an incredible fierceness, almost pulling itself though. I was also able to cut some raw Irish potatoes, carrots, and apples paper-thin (thin enough to see the kanji behind the flesh).

I hope you enjoyed the read. As always, if you have any questions or comments please feel free to post them and I will try to the best of my abilities to answer.

Great review, I love my hakka too, it is just superb stone to fill the 1k-6k gap if I am to estimate any grit ratings.
That's a good read. I've got one hakka, and it is a very nice stone to finish a lot of knives with.
I have so much to learn...thank you very much.

I'm glad you all are enjoying the reviews. A little later I will post a stone list, albeit abbreviated because I will not include my razor stones. If anyone is interested in a particular stone they would like to see reviewed they are welcome to choose it out of the list and I will do it next, or if anyone is interested in comparisons between stones I can do those as well. I think it will be easier than me trying to choose.

Very cool review, thanks for doing these.
Thanks Chris !! :thumbsup: Very cool writeup !
I am happy that you enjoying your stones :D
have fun !!
Looks like you scored a pretty special stone there. My old hakka was the first choice finisher for my double bevel knives, it made for a great pre finisher on single bevels as well. I recently sold it though as i preferd my new Hideriyama. Perhaps you could do a group review of your softer pre finishing stones. Personally the 2.5 ish stones are not only my most used naturals but also my favourites.
Hi Chris, I'd love to see hakka shoot out as well as atagoyama review. I'm on my way learning to use harder finishing stone.
Hi Chris, I'd love to see hakka shoot out as well as atagoyama review. I'm on my way learning to use harder finishing stone.

So, I have 3 other hakkas, one of them a suita. I currently have 1 atagoyama, but I also have a second on the way. Since I have all the necessary stones for a hakka shootout, then I will do that one first. Whenever my second atagoyama arrives (next month), then I will do a 2 part atagoyama review with each stone. Hope this is acceptable.

The other ones I was considering first were my other 4 suita stones. 2 Ohira Renge, 1 Okunomon, 1 Hideriyama.

Since you were the first to make a request, I will let you choose which you would like to see reviewed first.
Hi Chris,

That's very generous, thank you. Hakka shoot out has its merit and it interests me in that this would be a comparison of stones from the same mine, but different stratas. Looks like you have two suitas and two others. That' would be interesting.
Hakka Shootout it is then. Those take a little time to put together, so be looking for it in a couple weeks. To be clear, my 4 hakka stones are: 1 Hakka with Kan Patterns, 1 Hakka Renge (this thread, but I will also add it back to the shootout), 1 Hakka Renge/with light Kan Patterns, and 1 Hakka Suita. All are completely different stones in their speed and fineness. This should be quite interesting!!!

Awesome, somehow I assumed that this hakka with renge is also a suita ....