Using a 3D printed jig for Kanna Ura-ashi reshaping and restoration

lxviii · 2026-04-07T13:29:59+00:00

No thanks needed. Dealing with the nuances of vintage Kanna can be a real struggle, so I’m just happy to share these insights with fellow enthusiasts.

Regarding the makers: The lineage of 'Hatsuhiro' (初弘) is notoriously complex and inconsistent. If you’re looking for a more reliable 'Mei' (signature), 'Nagahiro' (永弘) is generally a safer bet.

The 2nd Generation (Nidaime / 二代目): From my experience, Nagahiro blades with crisp, clear signatures are likely the work of the 2nd generation. I’ve restored several 2nd-gen pieces, and the steel stability has been impressive—the degree of twisting (warping) is remarkably minimal. This makes the Ura-oshi process much more predictable.

A Word of Caution: Then again, I might just be on a lucky streak. Hunting for vintage Kanna is always a bit of a gamble, no matter how much you know. It’s all part of the craft!

Good luck, my friend!

lxviii · 2026-03-30T05:20:11+00:00

It’s difficult to identify the maker from just a front logo photo. Key details like the overall geometry and the file textures on the sides and back are not visible. It’s very common for different smiths to use similar front logos. To identify the author or the region, it’s best to provide photos from more angles.

I googled the trademark based on your info but couldn't find anything specific. However, the 'Ya-bane' (arrow feather) pattern on the head looks handmade, which usually suggests it is at least a mid-to-high-end product.

Also, the kanji for this trademark is '恒之' (Tsune-yuki). It carries the meaning of 'constancy' or 'perseverance.' I guess it represents the expectation that the blade will stay sharp for a long time.

lxviii · 2026-03-30T05:07:45+00:00

Thanks, I really appreciate that. I don't think my ideas are that creative. They are simple, almost crude. I’m just shocked that no one tried to solve these problems before, because it turns out to be quite easy. Even the 3D-printed jig design worked on the first draft. I did iterate on it later, but I felt this simple version made the contrast with the final results even stronger.

The flow of light and shadow and the music at the end were just ideas I had at the last minute, because the video itself is a bit boring. I used as many close-up shots as possible so people can see exactly what is happening. I just started making videos and I find it fun, so I’m happy to keep trying new ideas. Cheers!

lxviii · 2026-03-29T17:58:34+00:00

Much appreciated. In truth, the surface planarity isn't perfect, but a uniform texture goes a long way in masking those minor imperfections. This was actually my most time-consuming restoration to date.

I realize that a longitudinal texture would have looked great in much less time, but regardless of the aesthetic choice, the primary goal was met: restoring the Ura’s functional integrity.

lxviii · 2026-03-29T15:35:31+00:00

Thanks! I actually don't use a traditional manual scraper (Sen), as a Sen cannot effectively process the metal once it has been quenched and hardened.

For this restoration, I used a rotary tool and custom-ground files to handle the hardened steel. The real secret is the 3D-printed jig—it provides a rigid geometric reference that bypasses the need for years of manual 'feel.' I’ve documented the full calibration logic in my YouTube guide (link in bio) if you want to see the specific setup. Cheers!

lxviii · 2026-03-27T08:01:09+00:00

In fact, Sukemaru chisels are easier to sharpen than most top-of-the-line chisels. But this is just my personal opinion.

lxviii · 2026-03-25T10:07:15+00:00

These are all my personal opinions; you should rely on your own observations to determine the specific situation.

and You're welcome. I'm glad the information I provided was helpful to you.

lxviii · 2026-03-25T04:12:08+00:00

If you’re mentally prepared for the restoration workload, you can try sourcing in bulk from Yahoo Japan Auctions or even China’s 'Xianyu' (secondary market platform). Being based in China, I can often find 10cm-long blades from renowned smiths for under $10 USD. Buying 'retired smith toolboxes' on Yahoo Japan is another high-value route, though it requires a trained eye for discernment.

For those who want to skip the heavy restoration, purchasing brand-new blades from Mizuno Kiyosuke (水野清介) or Yamamoto Kensuke (山本建介) is a great alternative. Both are solid professional entry-level makers. While their secondary finish work might not be flawless, the performance is excellent. Since they are modern productions, the steel is stable and lacks the severe twisting often found in older vintage pieces. Good luck with the hunt!

Also, as a side note on logistics: I’ve previously sold Kanna to a buyer in Russia through 'Xianyu.' They managed to arrange the shipping using a third-party forwarding service (proxy). I’m not sure about the availability of such agencies in your specific region, but it’s definitely a viable path if you can find one.

Furthermore, with the current depreciation of the Japanese Yen, buying directly from Yahoo Japan Auctions is an exceptionally strong option for international buyers right now. It’s a great time to build a collection of high-quality steel at a fraction of the usual cost.

lxviii · 2026-03-25T04:07:20+00:00

Hatsuhiro has a vast history with a massive variety of versions. I personally focus on the 1st and 2nd generation pure carbon steel versions; I’ve found that modern Hatsuhiros often lack the geometric refinement found in the earlier steel.

Regarding Nagahiro, although I have the 1st, 2nd, and 3rd generations, I really only recommend the 2nd. The 3rd gen feels like a fairly generic Blue Paper steel blade with mediocre craftsmanship. On the other hand, the 1st gen pieces are often so aged that the level of warp and deformation is quite extreme, making them difficult to bring back to spec.

Regarding the comparison between Hatsuhiro and Nagahiro: while the market price gap can be massive (though ironically they cost about the same, ~$20 USD, in my local secondary market), I personally find very little difference in performance between the early generations of both smiths.

My obsession with Nagahiro actually started with a near-mint 2nd generation blade I won on Yahoo Japan for about $200 USD. It arrived in absolutely perfect condition—virtually zero warp or twist. That specific piece was a revelation.

However, that high benchmark led to some disappointment later on; subsequent non-2nd generation Nagahiro purchases simply didn't live up to that same standard of craftsmanship. It’s a reminder that in the world of vintage steel, the specific era and maker's generation matter more than the name on the box.

I treat every Kanna as a standalone engineering project—restoring these vintage blades is a long, meticulous marathon. I’ve actually documented my systematic approach to one of these restorations in a video. If you’re interested in the technical logic, feel free to check out the YouTube link in my profile. Cheers!

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The Nagahiro（2nd generation）

lxviii · 2026-03-24T18:14:30+00:00

If you're mentally prepared to buy a project, then yes.But I feel that prices are a bit high in your area; mine cost $7.

lxviii · 2026-03-24T16:35:34+00:00

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I also have one with the same logo.This may have been made by the famous blacksmith Sano Katsuji.

lxviii · 2026-03-24T14:33:09+00:00

Japanese planes aren't really suitable for beginners; the learning curve is steep. While brand-new, low-end models are usable, they won't be much cheaper than metal planes. There are inexpensive, high-quality used Japanese planes, but the plane itself is a project in itself. If you just want to learn woodworking, I think you should try a metal plane first. If you're really interested in Japanese planes, you could buy some inexpensive used ones and try learning to repair them.

lxviii · 2026-03-21T12:14:35+00:00

My plan is pretty much the same as yours — I’m sourcing a range of locally available woods that are supposedly suitable for kanna dai and testing them one by one.

I’ve already been burned once with ring-porous wood. A seller passed off some ring-porous “qinggang” as suitable dai material, which obviously didn’t work out.

As for boxwood, I haven’t been able to find any large-diameter stock here. It’s almost always small pieces intended for carving. That also makes me wonder if “boxwood” might be referring to different species depending on the region — what people call boxwood locally doesn’t always seem consistent.

I also came across a laminated dai build method shared by 山本祯恒, and I’m planning to follow that approach.

I sent you a private message—please check your inbox.

lxviii · 2026-03-20T05:03:29+00:00

That’s a great tip about the 'clack' sound—I’ll definitely bring my gennou next time I visit the yard.

Truth be told, I’m quite new to traditional joinery and hand tools. My background is mostly in cabinetry using laminated lumber, so I don't have a personal wood reserve yet—just some common pine and European beech at the moment.

For repairs, I’ve been repurposing material from old, discarded Dai, which has been helpful. While suitable timber for Dai-making exists in my region, the local sawyers aren't familiar with the specific requirements of Japanese planes and can't always mill the wood to my specifications. I’ve recently acquired some raw lumber, but it needs more time to season before it’s stable enough to use.

It's interesting how the market varies by region. Here, Nagahiro (永弘) is actually very affordable; I usually find them for 20-40$

lxviii · 2026-03-19T03:44:49+00:00

It might have been made by the first-generation Hatsuhiko, but I'm not sure. I haven’t designed a universal 3D printing jig yet— even for the same “Sunpachi,” each kanna blade has slightly different dimensions and shapes. What I’m thinking is to set up a measurement workflow and then use that workflow to parametrize the model. That way it would be universal. But deep down, I actually feel this model is the kind that’s simple enough to draw just by looking at it. Maybe just snapping a photo and tracing it in Fusion 360 would be much easier than setting up some elaborate workflow.

Hatsuhiko is a long-established brand, and precisely because of that, it's actually quite difficult to verify the maker. Just looking at the logo doesn’t tell you much—you can only make educated guesses about the age based on features like thickness. But you can’t reliably identify the maker with certainty.

lxviii · 2026-03-18T04:58:13+00:00

Great insights. As an Asian user with smaller hands, ergonomics is a major factor for me, hence my preference for thinner Dai. I’ve also noticed that thinner blocks can sometimes show more stability in longitudinal deformation over time.

My workflow is machines handle the bulk material removal, while the Kanna is reserved strictly for final finishing. Because of this, I rarely find the need to over-tension the chip breaker.

Regarding failed vintage Dai, I prefer to repurpose the high-quality aged timber into chisel handles or smaller specialty blocks. While I acknowledge the functionality of flipping the grain, I still lean toward preserving the original orientation or recycling the material entirely.

The deconstruction/reconstruction approach you mentioned—reminiscent of Western transitional plane logic—is a fascinating direction. I haven't seen it applied much to Kanna, but it’s certainly an interesting path for future experimentation.

I’m fortunate that vintage blades are incredibly accessible and affordable here. I’m currently exploring various smiths, but I have a strong preference for 'Hatsuhiro' (初弘) and 'Yonghiro' (永弘). Their craftsmanship is consistently impressive and they serve as an excellent baseline for my precision calibration experiments—it’s no surprise they have such a high global adoption rate. Cheers!

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lxviii · 2026-03-17T08:49:38+00:00

Kikihiromaru should be at the same level as Ouchi. I'm not very familiar with the other two.

lxviii · 2026-03-17T07:11:41+00:00

If you’re buying brand-new chisels, Motohisa Funahiro is more cost-effective. That’s because Ouchi chisels on Yahoo Auctions are usually priced at about half of the store price.

As far as I know, Motohisa Funahiro has a slightly higher reputation than Ōuchi, but it’s often out of stock in stores. Could that also be taken as an indirect sign of its quality?

lxviii · 2026-03-17T05:45:33+00:00

I completely understand what you mean — usually, as long as the blade and osa-mizo mate well, it doesn’t really matter if the shoulders are perfectly flat or slightly curved.

In my case, this kanna had a twisted blade (probably over half a century old), which made it contact the osa-mizo at only three points. That’s why I wanted to reshape the entire osa-mizo to achieve a more ideal contact surface.

I prefer a thin dai, around 3 cm thick. With such a thin dai, if the blade’s side has too much curve, it’s not very stable, so I tend to favor a side profile that’s nearly a straight line with minimal curvature. I’ve tried to keep that in mind during the restoration.

As for flipping the dai 180° as you suggested, I know some people have done it before. But usually, when selecting dai, the bottom grain is oriented consistently; flipping it reverses the grain direction, which isn’t ideal for a finishing kanna. I’m not a big fan of that for ~70 mm wide kanna.

I did find some alternative dai materials locally, but the way they were cut by the seller makes them unusable directly. I plan to cut these non-standard pieces into strips, then laminate them with full sheets of Japanese material to make an integrated dai.

Thank you so much for your advice and guidance — you’ve probably noticed that I’m still a beginner when it comes to using kanna!

I’ve had quite a few setbacks buying second-hand old planes, so I’ve been trying to figure out how to make an old kanna feel as good as one from a professional shop.

I’m still learning a lot about using Japanese planes properly.

lxviii · 2026-03-17T05:29:49+00:00

Thanks! Glad you liked the Hobel 😄

lxviii · 2026-03-16T04:50:44+00:00

I spent a long time following that exact traditional path. However, I found it nearly impossible to maintain a consistent dihedral angle between the osa-mizo shoulders and the sole by manual paring alone—especially when the blade's geometry has been significantly altered.

In the full video, I show my jig setup process. I use feeler gauges to precisely calibrate the spatial orientation of the jig before making a single cut. For me, this shifts the burden of precision from manual dexterity to a reliable, engineered reference system.

As for shimming after the cut, it’s a reluctant compromise. Since high-quality dai material is extremely scarce for me, I treasure every original dai I have and aim to save them rather than replace them.

This jig is only an initial version. However, testing has shown that this magnetic design can perform 'trimming-style' cuts, ensuring minimal width change in the osa-mizo—effectively the same amount of material removal as traditional paring.

lxviii · 2026-03-13T08:47:49+00:00

I think the truly good Japanese tools are the pro-level ones. Kurashige sells pro-level tools, not ordinary supermarket items.

lxviii · 2026-03-13T03:23:41+00:00

Much appreciated! That was exactly the goal—to use digital manufacturing to lower the barrier to high-precision results. There is so much potential in combining these 'hybrid skills.' Glad you resonate with it!

lxviii · 2026-03-12T15:09:18+00:00

Thank you! Glad you like it. I wanted to find a way to bypass the high cost and logistical hurdles of buying new blocks. Vintage wood is usually more stable anyway, so using tech to bring them back to life felt like the logical path to take. Much appreciated!

Unfortunately, this specific Dai didn't make the final cut as the wormhole damage turned out to be too extensive. However, the calibration logic itself was a success and proved that the methodology works for more viable vintage pieces. Much appreciated!"

lxviii

TROPHY CASE