Thread: Ozuku Asagi (Koppa)

Well...I received my stone today, took it out of the box, un-wrapped it and thought "oh no!!"



Decent size stone but look at those darn streaks. They are not cracks but a fine layer of alternate material. I figured at least I know where to cut it to make some rub stones but decided to give it a try. Maybe those lines are not toxic.



Broke out a Dovo that has been giving me problems, put down a slurry with an old DMT, and got to work. The stone had great feedback and no hesitation or skips along the cracks. Looked at the bevel under a loupe and didn't notice any unusual wear. Finished up with straight water and experienced a little chipping. I then stropped it with cro ox, linen, leather, and then back to the stone. Finished it with some lite circles and X strokes. Re-stropped and it gave a decent shave.

I next broke out my Boker and took it through a normal progression starting off with a slurry.



3 sets of heavy to light circles and then about 20 laps of X strokes.



I then diluted down to straight water and then finished up under running water. This razor was tree topping and hair was popping. Took it to the strop, no cro ox, just linen to leather and took off my goatee with very little effort. This razor has never been this sharp. The real test will be a 3 pass shave but I am extremely happy with this stone so far.

Looks a great shape considering the Koppa designation. Lots like that palm sized stone and wouldn't call it a compromise, but a benefit. As long as the streaks aren't made of the same material as the skin, (Discoloured bottom or skin, that seems to extend up one side of the stone) you should be right, you definitely don't want to lap the stone into the skin that appears on one of the sides, as they are toxic and ruin the edges. All things being equal if you got a sharp edge then that's all that really counts. Well done and your thread has been helpful to all of us, thanks Bob

Originally Posted by bobski

Looks a great buy mate. The Koppa, are a bit like coticule 'bouts', odd sized bits, but you can get a good one, with luck. I looked deeply at the jnat market, and ended up buying a full sized Ozuku Asagi double sided 1.6kg stone that is a great hone to sharpen razors. Thing is they are expensive, but this one will last me generations. (photo on 'hone of the day pages 167). I've been in the garage with a sleeping bag when it arrived....lol, but I'd love to see you get a good one, and show us when you can.

I've had about 40 jnats. One of the fine razor finishers I had was an ozuku koppa from CKTG. It was as good or better than a lot of bigger more expensive stones that I've used, only faulting a little bit on slowness (which isn't an issue for razors - you can tease performance out of a slow stone, but you can't tease smoothness out of a scratchy stone). Best stone I've had was a stone about koppa size that I paid a lot more for, but I paid a dealer to find me performance and it cost a lot. An ozuku koppa is plenty of stone for several lifetimes of sharpening if you're sharpening just your own razor.

re: using it as a rub stone, you'll need to hack saw a cross hatch pattern on the surface of it if you want to do that. Hard smooth stones that don't release particles don't make the greatest rub stones. Their particles are usually a bit harsh when they break free and they don't make a nice easy uniform slurry that a softer stone makes. But you can work with them. I cut my koppa up ultimately and learned that (I cut it up just because I had too many stones and thought I had a good source for four $15 tomonagura, but found out the lesson of tomonagura usually being fragments from stones on the soft side).

I made my first post before reading that you received the stones. You can ignore those cracks - they're common and no threat if they don't have particles in them (cracks that do usually are larger and so are their particles).

I'd encourage you not to cut that stone up for any reason. Stone value in japan is a funny thing - small stones aren't worth much (their small stones are bigger than extremely expensive thuris) on the domestic market there unless there is something extremely rare about them (for example, a perfectly uniform very yellow fine and soft kiita). You will see shystery sellers in the US trying to sell pedestrian relatively new koppa sized stones for a couple of hundred bucks or small tsushima for a couple of hundred bucks, but those things sell for very little in japan. You did well, and you'll probably find that stone to be as good as about anything you get - don't be swooned by expensive stones - the very expensive stones usually have an aspect that is 90% rarity for characteristics other than sharpening ability. Even then, I'd watch yahoo auctions in japan to see what the stones bring domestically. A karasu stone that someone would try to re-sell for $800 in europe or the US will often sell for a small fraction of that in japan.

I tend to agree with you Dave, but not a lot blokes have a resource like your 40 stones. I think the main thing when buying a jnat, buy only from a reputed source. Generally the market decides the price, and if you buy from a reputable source you can confidently expect that you get what you pay for. When I bought jnats, I wanted quality finishing stones for straight razors. I didn't ask for pre finishers or anything other than hard fine finishing stones. I ended up with an Ozuku Asagi and a Wakasa. They weren't cheap, but they are top quality and I got what I expected. Very hard and fine finishing stones. Full sized, and double sided. Their cost is immaterial when you seek out a certain type of stone. Some carpenters pay big money for a suiita, that isn't what I want. I wanted and received top quality stones that are in my eyes worth their price.

Originally Posted by bobski

I tend to agree with you Dave, but not a lot blokes have a resource like your 40 stones. I think the main thing when buying a jnat, buy only from a reputed source. Generally the market decides the price, and if you buy from a reputable source you can confidently expect that you get what you pay for. When I bought jnats, I wanted quality finishing stones for straight razors. I didn't ask for pre finishers or anything other than hard fine finishing stones. I ended up with an Ozuku Asagi and a Wakasa. They weren't cheap, but they are top quality and I got what I expected. Very hard and fine finishing stones. Full sized, and double sided. Their cost is immaterial when you seek out a certain type of stone. Some carpenters pay big money for a suiita, that isn't what I want. I wanted and received top quality stones that are in my eyes worth their price.

I'm on both sides of the fence. I asked alex a long time ago to give me the best finisher he could find out of his small stones for (I can't remember the price, maybe it was $200 or something). I asked him to go 100% on performance and 0% on looks. He returned a multi-colored ozaki stone that was the nicest I've used for razors for a little less than my limit. I was in a pickle when I finally sold it, I'm not alex selling it so nobody has incentive to believe me. I ultimately got $95 for it. I learned a lot, and have always enjoyed doing business with alex as I can tell him what my budget is at the time for a need and get performance.

At the same time, someone who buys one of these koppa from CKTG essentially has no risk. There is very little market in japan for a stone the size of these koppa, so despite the fact that they're as cheap as about $65 here, they go for almost nothing on the auction sites in japan. That allows us to get good stones for relatively little, and the two best razor stones I've had were one koppa from CKTG and the stone I got from alex. I'm sure I could've waited until my koppa stone was out of stock at CKTG and sold it for the same as I paid for it. Or sent it back if it wasn't what I wanted.

Dark green stones and unmarked green stones of a lot of types are very fine stones quite often, sometimes not the fastest, but plenty fine. On the japan auction site, you can take a risk on some of them for about $30, unless someone puts stamps on them (that are probably fake, at least based on what I see on some stones that look like they're nowhere close to the stamp standards), sometimes less. For fun, I ordered a couple of stones from japan this past week. I have also purchased large stones for up to about $500 in the past, and some less than that. Where I divert from the dealers is when they're selling something commodity and asking a big price. For example, if someone is selling a large atagoyama hone of no special provenance and asking $700 for it while they sell all day in japan for $250 - or less, I can't really get on with that. Same stamp, same stone, just a tax for unfamiliarity as far as I'm concerned. The dealer isn't adding value in that case.

There was a seller in the woodworking world who had gotten GOBS of dark green ohira type 30 and type 24 stones. I saw a type 24 stone of that provenance sell last week on the japanese site for about $200. It was used, but unused (NOS - I suppose they all are). I had gotten one of those from a seller in the US years ago. $390 for a type 30 stone. The stone I got wasn't very good. It had size and little else. Not a fast cutter, not particularly fine. The type 24 stone was about $800 from the same seller. I sold mine to someone for $150, that's all I could get for it, and then a year after they got it from me, it delaminated. I felt bad for several reasons.

Fast forward a couple of years later, and I brought the topic up on a woodworking board, and several people said they tried natural stones with unspectacular results. They had gone to a seller who had imported all of these green stones - different retailer than I used, but same supply. In each case, the advice back then was to ask a dealer to select a stone for you based on the tools you used and the steels in those tools. In every case, the dealer returned and said they had specially selected a stone for each person (none of these people were talking to each other). Each person received exactly the same stone - one that the dealer likely got for very little money (relatively) and then sold - the dark green ohira tomae stones like the one I got. Or more specifically, people paid a lot of money for someone to select a stone for them, but the person doing the selling did nothing other than sell what was best for them to sell - and it wasn't a particularly good stone.

I don't know what the ultimate lesson from all of this is other than that nothing is guaranteed. I do wish I'd have kept the small stone I bought from Alex, though! A hard stone 1/2 inch thick is enough for several lifetimes of honing to me. Curiosity about the next thing sometimes causes me to sell something I should've kept.

Like OP, I bought a CKTG Ozuku Asagi Koppa as a means to check out the jnat world. Got it from the latest batch and it arrived yesterday. Upon recommendations here, I let the seller know that I would be using it on razors. His response was that all of the ones he sells go to razor users.

It is a gnarly looking thing with no straight edge to work from. However, I ran an old tester blade accross it a bit and it felt really nice - but, what do I know? It was mostly flat.

Here it is after I first played with it.





Unwilling to wait and ask my betters here, I ground on it - dremel grind stone and diamond plate. I mostly ground the sections where the red boxes are. I wasn’t trying to get flat sides, just straight edges across top edges. Then chamfered and lapped. Looks much better now with 3 straight sides.

Got mine a few months back and liked it. Need to use it a lot more when I get some time at home. Here are some picks when it arrived.

I got one from Mark quite awhile ago and ended up selling it as it was a weird shape that I had to do kind of an S shape stroke to get full use of the stone, not a bad price for a JNAT but to small and irregular for me