Tsukasa 210mm Rentetsu-ji Ken-nata w/ Saya (ON SALE!!!!!)


Stock reduction 20% off sale!

I have owned this knife for 3 years now, but..., unfortunately, I could not find too much tasks, well, to be honest, not at all, for me to heavily put this knife to usage.

Apart from Katanas I like to actually use my tools, heavily, but this was not possible for me with this gorgeous baby since I don't hunt.... Hence, reluctantly letting go.

It is IMO THE most beautiful Ken-nata by Tsukasa-san.

Price wise, twisted Kitaeji "Unryu" model would be noticeably more expensive, since it takes much more time and effort to prepare the Kitaeji material, by laminating two metals and folding over carefully to create the patterns. But, I have never owned this knife myself.

This is because, to my eyes, the natural, and reserved (not as readily visible as Kitaeji or etched Sekisou pattern), yet very complex pattern of Rentetsu (very old British wrought iron, from pre 1900) or Watetsu (byproduct wrought iron of Tamahagane smelting) is more attractive, altho this is just my preference. Tsukasa-san folding the Rentetsu material also adds complexity to the rendered pattern.

In Katana world, blades with loud and gaudy Hamon or Ji are often favored by novice Katana fans, but connoisseurs basically always end up pursuing reserved but complex and deep blades, with very fine and compressed (i.e. harder to see, because) Hada (skin, which refers to the damascus like folding pattern seen on the entire blade) resulting from more numbers of folding. This, I understand, is because, loud and gaudy patterns bore the beholder very easily.

For those of you who enjoy wine, this analogy might be a good way to explain. The difference that I speak of above is similar to that of say less expensive new world big reds (cab savs, shiraz) vs. very fine and elegant Pinot Noirs, from Bourgogne, France, southern Victoria, Aus (Mornington Peninsula, Yarra, etc), Central Otago, NZ, or Sonoma, Cailfornia.

I almost forgot to mention about it's performance, absorbed in explaining it's beauty. Tsukasa knives, IMO, boast THE most durable edge among all J knives. They are made with Tsukasa-san's signature WS#2, this is with intention.

There are quite a few knives made using WS#1, but..., when it comes to knives, especially those longer than perhaps 150mm, because a larger surface of steel needs to be laminated, it is very very difficult to forge knives with pure carbon steel.

When laminating steel on to mild steel, or sandwich with, the only glue is the powder glass called Housha. You need at least a certain amount of this powder to gain proper lamination, and it is the less the better. BTW, the giant, Yokoyama kanna smith, used so little when laminating, it was almost scary....

Now two things can make this lamination process much much easier. One is if the steel is an alloy (I'll omit the details for this one.) Another one is, by using higher heat, which is a problem. By using higher heat, the steel will decarburise, i.e. the carbon will evaporate and hence the steel will become softer, so for e.g. even if the smith proudly advertises his knife to be made of WS#1, if the forging, including the very difficult lamination, was done by higher heat, the WS#1 will be equivalent to #2 or even #3, which IMO, is often, or almost always(?) the case.

Knives and tools with unclear lamination line are such cases. The total opposite is when you see a slight gap between the steel and the mild steel, which some of you may have thought to be a minor fault, but no no, such is the tool with ideal heat management. Again, Yokoyama-san, his tools often had such minor lamination gap, that is because he laminated with so little Housha, with super low heat. He was a genius of steel lamination. He often said "I can forge Swedish pure carbons (referring to difficult steels like Bohler 990K, or Assab K120) with my both eyes closed."

Tsukasa-san being a knife specialist, he is well aware of this, and hence chooses his choice ingot WS#2 as his signature steel, and ca~~~~~~~~~~~~~refully forges with his Iwasaki trained skill. Also, other famous knife smiths, like Shigefusa, Heiji-san, Kato-san, etc. all intentionally use steels equivalent to WS#2.

As many of you may know, I am a sharpening addict, my hands will start shaking if I don't sharpen anything for too long. So..., for me, Tsukasa-san's knives and Natas have one major problem(????) which is that they don't let me sharpen them as often as I like..., hahaha. Really, his knives are THAT durable. I have been hacking thick branches and thinner tree trunks with my Nokaji Nata, and the edge just lasts and lasts and lasts, and ne~~~~~~~~~~~~~~~~ver chip, basically no matter what.

The steel being so hard, I had initially thought that it may be a bit brittle, but this was totally not the case. I accidentally dropped it on to a cement surface, and I was surprised to see that the edge at the tip only mildly got dented, but not chipped.

Users who are not too familiar with the highest of the highest quality tools may think, "Is denting not a sign of the steel being soft???" and yes, it is, but it is also a characteristics of the best of the best most robust tools as well, for a different reason, resulting from highly refined carbides (C + Fe.)

This is something you just need to experience to believe. Such tools always share three characteristics, 1. they bite well to the stones = easier to grind, with more feel, does not slip on the stone, 2. the edge becomes very very very keen, and 3. the edge lasts and lasts and lasts, and yet does not chip, very very very durable.

You should easily be able to imagine how I get to try and test ma~~~~~~~~~~~~~~ny tools, but perhaps never thought of how much I get to own and use? But if you will think about it, I can only own and use so many tools, so tools that I actually own and use myself, you see, that means something!

So all in all, this knife is the most sought after knife made by one of the most famous, most skilled smith in Japan.(^^)

But since I cannot use it..., I will have to let it go.... I hope it will find a good new home.

Wow!! That came out long! Thanks for reading!



This knife is in Australia, the shipping might need to be adjusted depending on the destination.

The wooden parts have been carefully oiled with wood treatment oil. The protective lacquer applied to the blade is a bit scraped since I have used this knife a few times, but by taking of the lacquer it will go away. If you wish me to do this for you, let me know.

Lastly, the price is with the old pricing from ma~~~ny years ago, it will be about at least 30% more if newly ordered, and you will also be facing..., a very very very very long and indefinite wait, up to..., 3~5 years or so!!!

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This product was added to our catalog on Sunday 05 July, 2015.

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