Kaiju and TF Steel

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G'day hivemind,

After using many a knife, I have discovered that the only two knives I have never sharpened and at this point seem like they'll never need sharpening are my Konosuke Fujiyama Kaiju and my Teruyasu Fujiwara Denka. Now my understanding is that my Kaiju is Blue 1 and my Denka is Blue Super. I also absolutely love the way these two steels perform, and they are both just all around excellent knives. So my question is, what is it about these two steels that make them so great, and what else will perform similarly.

To elaborate some more, Tanaka's Blue 1 and TF's AS are probably my favourite core steels. I want to understand what it is that makes these so remarkable. I also want to know what else might be comparable. For example are there things like "well if you love Tanaka's Blue 1, you're gonna love Kamon's 1.2519" or is AS basically the same as some other steel that western makers are using?

Basically, I've acquired a taste, but I don't know why... and I want more.

Thanks for your time!
Luke
 
That's exactly what I was starting to wonder. If things like magna cut and apex are even better.
They are in a way different league, aogami for example has very simple, large carbides (except super you do get some more spicy additions)

This is the holy grail really, Larrin from knife steel nerds testing edge retention of tons of commonly used steels at different HRC's. Look how far down even aogami super is, and blue 1 would be quite a bit lower than that, like around the v-toku 2

That being said, TCC is cutting silica impregnated cardboard, which is different than what we use our knives for of course, but it's a good way to compare steels back to back

edge.png
 
Here is how apex compares to other carbon steels, it's at the top for the more "simple" carbon steels.

apex.png


If you want to get one of the crazier high edge retention steels, I would highly recommend Andrei Merkin @Andrei who works with s90v, m390, rex121, k390, etc. @Blank Blades. also is working on 10v and k390. Harbeer @HSC /// Knives would also be a good choice using z wear which is similar to cruwear, along with magnacut, apex and others, so is @MSicardCutlery

Cool thing about magnacut is while having a lot more edge retention compared to aogami super for example, it's also quite a lot tougher. And stainless of course. I would recommend to get diamonds for sharpening for all of these steels though.

I can personally recommend Andrei's work, as well as Will Newhams, his magnacut is really great. The others listed I have also heard great things about, but have never used anything from them before.
 
If you try something like magnacut you could reliably get about,double the edge retention of blue steels, ZDP-189 or s90v triple
TF AS has been my fav steel for some time. But there are other factors to consider. ZDP189 (not familiar with the others so can't comment) is a harder steel but that translates to it being less user friendly when it's sharpened and honed. The beauty of TF AS steel is that it is a joy to sharpen, achieving hair shaving sharpness without a lot of fuss. And while the steel doesn't require regular attention like W#1 it can certainly benefit from the occasional strop before needing a proper sharpening progression.
 
I’d say the edge stability also has a lot to do with edge retention, in many cases a steel that managed to maintain a more acute edge is gonna out cut a steel that crumble at the same thinness or angle. Good thing about Blue 1 and Denka blue super is that they are easy to get to that degree of acuteness without crumbling, they in a way they are way more easy to get there than high alloy steel. That makes them very enjoyable to use
 
TF AS has been my fav steel for some time. But there are other factors to consider. ZDP189 (not familiar with the others so can't comment) is a harder steel but that translates to it being less user friendly when it's sharpened and honed. The beauty of TF AS steel is that it is a joy to sharpen, achieving hair shaving sharpness without a lot of fuss. And while the steel doesn't require regular attention like W#1 it can certainly benefit from the occasional strop before needing a proper sharpening progression.
I actually find ZDP a breeze to sharpen, at least on my sukenari. Benefit from chromium carbides, it was designed to be sharpened on waterstones. But yeah of course carbon steels are always gonna be more pleasurable
 
B1 is my favorite steel in terms of retention and sharpness combined, but with the sacrifice of being more reactive and easy to rust. But but, that makes it a good excuse for me to buy more polishing stones..? 🤔
 
I’d say the edge stability also has a lot to do with edge retention, in many cases a steel that managed to maintain a more acute edge is gonna out cut a steel that crumble at the same thinness or angle. Good thing about Blue 1 and Denka blue super is that they are easy to get to that degree of acuteness without crumbling, they in a way they are way more easy to get there than high alloy steel. That makes them very enjoyable to use
I suspect with the data I have seen at least apex ultra probably has fairly good edge stability. I havent been able to buy any when its been dropped so i don't have first hand experience with it. But i think it will do well in that regard.

A lot of the powder metallurgy semistainless tool steels i find have great edge stability. Given the right heat treatment at least. Which is a big part of why I like them, without me getting into all the other stuff i like about them, and derailing myself.

I haven't tried zdp-189 personally, so i can't comment much about it. What I will say is having that high of a carbide volume likely hurts the edge stability a bit, just like rex 121 might have such a large carbide volume get into the way of that. So for me I tend to find a bit lower volume to be the sweet spot for that.
 
I suspect with the data I have seen at least apex ultra probably has fairly good edge stability. I havent been able to buy any when its been dropped so i don't have first hand experience with it. But i think it will do well in that regard.

A lot of the powder metallurgy semistainless tool steels i find have great edge stability. Given the right heat treatment at least. Which is a big part of why I like them, without me getting into all the other stuff i like about them, and derailing myself.

I haven't tried zdp-189 personally, so i can't comment much about it. What I will say is having that high of a carbide volume likely hurts the edge stability a bit, just like rex 121 might have such a large carbide volume get into the way of that. So for me I tend to find a bit lower volume to be the sweet spot for that.
My experience with ApexUltra is very good, I feel it is actually better on stone than Deep Impact AS, tho TBH the edge retention are both excellent for kitchen use id have a hard time to compare without doing some sort of rope cutting test
 
They are in a way different league, aogami for example has very simple, large carbides (except super you do get some more spicy additions)

This is the holy grail really, Larrin from knife steel nerds testing edge retention of tons of commonly used steels at different HRC's. Look how far down even aogami super is, and blue 1 would be quite a bit lower than that, like around the v-toku 2

That being said, TCC is cutting silica impregnated cardboard, which is different than what we use our knives for of course, but it's a good way to compare steels back to back

View attachment 263059
Ok, so what I don’t get is that (at least by my uneducated reading) this chart suggests that if our primary concern is TCC score, then VG10 at <62HRC is leagues better than blue super even at 65HRC, and SG2 is better than Magnacut at the same HRC. And yet very few (to no) people are here waxing lyrical about either of these steels.
 
Ok, so what I don’t get is that (at least by my uneducated reading) this chart suggests that if our primary concern is TCC score, then VG10 at <62HRC is leagues better than blue super even at 65HRC, and SG2 is better than Magnacut at the same HRC. And yet very few (to no) people are here waxing lyrical about either of these steels.
CATRA is a great way to test slicing edge retention of steel that’s sharpened to same angle and same thinness, and also correctly heat treated individually. But that’s not the case in real world, there’s just too many variations in manufacturing, Cedric and Ada also does rope test with their knives, still not reflective of kitchen uses but you can see in some cases their result did not line up with CATRA, both are valid just different scenarios
 
Ok, so what I don’t get is that (at least by my uneducated reading) this chart suggests that if our primary concern is TCC score, then VG10 at <62HRC is leagues better than blue super even at 65HRC, and SG2 is better than Magnacut at the same HRC. And yet very few (to no) people are here waxing lyrical about either of these steels.
A little bit irrelevant on the magnacut end, since that is only if magnacut is at 61.5. Most makers usually run it 63-64 where you would see a decent improvement on SG2 in that department.

However, no one is saying magnacut is a king of edge retention. Remember, this chart is only showing relative edge retention. That is it. Even at 63-64hrc, magnacut is tougher than 61hrc SG2, and is more stainless, along with it having a finer microstructure so potentially keener edges. It is an extremely balanced steel which is not super common among PM steels. That being said I love SG2. I wax about it. It was my favorite stainless kitchen knife steel before magnacut.

And again, VG10 example, yeah it has much higher edge retention than blue super, but it is also not very tough at all (neither is blue super). SG2 has better edge retention and toughness, which is why I say there isn't much of a point to VG10.
 
A little bit irrelevant on the magnacut end, since that is only if magnacut is at 61.5. Most makers usually run it 63-64 where you would see a decent improvement on SG2 in that department.

However, no one is saying magnacut is a king of edge retention. Remember, this chart is only showing relative edge retention. That is it. Even at 63-64hrc, magnacut is tougher than 61hrc SG2, and is more stainless, along with it having a finer microstructure so potentially keener edges. It is an extremely balanced steel which is not super common among PM steels. That being said I love SG2. I wax about it. It was my favorite stainless kitchen knife steel before magnacut.

And again, VG10 example, yeah it has much higher edge retention than blue super, but it is also not very tough at all (neither is blue super). SG2 has better edge retention and toughness, which is why I say there isn't much of a point to VG10.
Yeah. Important I think we don't get lost in the weeds of purely wear resistance. When talking about good steels to use. Tbh, its really easy to overemphasise steel. While it is certainly important. In fact one of the 3 most important things to a knife (geometry, steel, heat treatment). Its easy to get carried away worrying about which is the best in different ways.

As much as I love my high wear resistance steels. Edge stability, toughness, and corrosion resistance will effect edge retention also. So when looking at what steels we might want to use, we need to take it into account. If at the thin geometry we want, it dulls by chipping out on something, or the edge deforms, or if you are cutting a bunch of limes and the edge corrodes, then even the most wear resistance won't help.

Generally a balanced steel with all of these categories is ideal (like you mentioned about magnacut). Since its basically like cpm 4v, but super stainless. And for the longest time before magnacut in order to get the kind of properties that it has you had to use steels that didn't have enough chromium in solution to actually be stainless, since they were the only ones that had the great balance of toughness and wear resistance. And they also do have a boost in corrosion resistance over carbon steels. The only drawback magnacut has compared to 4v, is you can't get it above 65 hrc (or around their). Not that you would need to.

I know i typed this as a reply to you @jedy617. But really i just wanted to say this for people that might not already have an idea about this stuff. To hopefully keep them from putting too much importance in the wrong places. Since its easy to get carried away with this stuff.
 
I have to call total BS on the graph, a lot is going to depend on the blacksmith and his methods.

Next, in real world applications things like geometry, cutting board surface, the item being cut, way of cutting, are all going to have a massive impact on the total experience.

Also, for real world situations, if you have steel (A) that only needs to be sharpened once every six months and steel (B) that only needs to be sharpened once a year does it really matter, is anyone really going to notice at that point?

One of the worst knives I’ve ever owned was ZDP, incredibly difficult to sharpen, and it chipped constantly, but I bought it because “HRC”, right?
 
I have to call total BS on the graph, a lot is going to depend on the blacksmith and his methods.

Next, in real world applications things like geometry, cutting board surface, item being cut, way of cutting, are all going to have a massive impact on the total experience.

Also, for real world situation, if you have steel (A) that only needs to be sharpened once every six months and steel (B) that only needs to be sharpened once a year does it really matter, is anyone really going to notice at that point?

One of the worst knives I’ve ever owned was ZDP, incredibly difficult to sharpen, and it chipped constantly, but I bought it because HRC, right?
The graph only compares steels to each other. Takes out the whole maker, cutting board surfaces and user part of the real world use.

It's not comparing different makers and how they used a certain steel (for example the edge being to thin for the steel, sharpening skills and stones used).
 
I have to call total BS on the graph, a lot is going to depend on the blacksmith and his methods.

Next, in real world applications things like geometry, cutting board surface, the item being cut, way of cutting, are all going to have a massive impact on the total experience.

Also, for real world situations, if you have steel (A) that only needs to be sharpened once every six months and steel (B) that only needs to be sharpened once a year does it really matter, is anyone really going to notice at that point?

One of the worst knives I’ve ever owned was ZDP, incredibly difficult to sharpen, and it chipped constantly, but I bought it because “HRC”, right?
How is the graph BS? It is testing using scientific standards (TCC) done by someone with a PHD in mettalurgy using very expensive equipment and sound methodology... the only changing variable is the HRC. I think that's a little insulting to someone who has devoted their lives to the study. If you want to read about testing methodology, here you go: Which Steel Has the Best Edge Retention? Part 1 - Knife Steel Nerds

I think there is too much mysticism placed on blacksmiths and methods. You use an evenheat oven, and can even cryo with a freezer and get the HRC results you are looking for, by following publicized heat treat recipes.

What stones did you use to sharpen ZDP? I form a burr in 5 minutes on a chosera 800. Also never chipped it. I have chpped AS though?
 
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Also your point about sharpening every 6 months vs a year doesn't make sense either. I have an s90v gyuto. As stated, it's more or less 2.5x + the edge retention of aogami super.

Now I'm lucky enough to have lots of knives, but back in the day one of my only knives was aogami super and I'd sharpen it every few weeks. Sooo 2.5x that if my s90v was my only knife... You can see where I'm going right?

Regardless, not everyone wants to be constantly sharpening. It's nice knowing that I have knives in my rack that I can depend on being sharp for a long time. Why can't people enjoy edge retention? Especially in a professional setting it seems quite useful.
 
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From a personal experience, High MC carbide and high hardness steel turns to be a lot more wear resistant, but some more “regular” stainless like SG2 and VG10 are hard to discern from lightly alloyed carbons like blue or 52100, as you can see in the Cedric Ada chart, he tested Vtoku2 more than VG10, SG2, 440C and even HAP40, of course this has alot of variables like thinness, manufacturers and stuff, and can show that the edge retention of individual knives are not absolutely decided by their steel
 
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G'day hivemind,

After using many a knife, I have discovered that the only two knives I have never sharpened and at this point seem like they'll never need sharpening are my Konosuke Fujiyama Kaiju and my Teruyasu Fujiwara Denka. Now my understanding is that my Kaiju is Blue 1 and my Denka is Blue Super. I also absolutely love the way these two steels perform, and they are both just all around excellent knives. So my question is, what is it about these two steels that make them so great, and what else will perform similarly.

To elaborate some more, Tanaka's Blue 1 and TF's AS are probably my favourite core steels. I want to understand what it is that makes these so remarkable. I also want to know what else might be comparable. For example are there things like "well if you love Tanaka's Blue 1, you're gonna love Kamon's 1.2519" or is AS basically the same as some other steel that western makers are using?

Basically, I've acquired a taste, but I don't know why... and I want more.

Thanks for your time!
Luke
I'd just like to second the people who are saying that the steel isn't the main factor in this case. Im not sure about the Kaiju line but the Denka's I have seen are all extremely finely ground behind the edge which I find really contributes a lot to that feeling of "this knife can cut forever without being sharpened".
 
I have to call total BS on the graph, a lot is going to depend on the blacksmith and his methods.

Next, in real world applications things like geometry, cutting board surface, the item being cut, way of cutting, are all going to have a massive impact on the total experience.

Also, for real world situations, if you have steel (A) that only needs to be sharpened once every six months and steel (B) that only needs to be sharpened once a year does it really matter, is anyone really going to notice at that point?

One of the worst knives I’ve ever owned was ZDP, incredibly difficult to sharpen, and it chipped constantly, but I bought it because “HRC”, right?

You can't just take the graph alone and try to apply it to real world applications. That wasn't the intent of it. You should read the entire article to understand what was being tested and why. It was a highly controlled test that has become renown among steel and knife makers.

You're correct that you can't just take those results and apply them across the board. It's just another piece of data that can be applied to make a broader decision.

It is all a trade off. There is no magic steel, not even MagnaCut. :)
 
I think there are some compounding factors.

For as good as Tanaka's HT is, and I do like it a ton, I feel like if Togashi didn't have his son sharpening all his blades it would change the way we talk about Tanaka's heat treatments a lot.

And look, I get it, it's his son. And Kenya is honestly pretty good, especially more lately (his convexes are just straight up good, the hollow wide bevel thing I don't like but yeah it's maybe not as good as some other folks). But Tanaka has the best sharpeners grinding his blades.

Anyway the only Japanese steel that I've put on stones and really felt like stood out from the relatively crowded group of good smiths is Nakaya Heiji's carbon.
 
I also love AS but in this case I think the maker and specific knife matters as much as the steel. The Denka has the reputation of having amazing steel. By all accounts it’s a unique treatment (either heat treat or grind) that stands out from other makers’ knives with the same steel, which is what contributes to the TF cult.

Rather than focusing solely on the steel, you might want to focus on other highly regarded maker + steel combinations. Yoshikane SKD is an iconic combination, for example - and mine certainly goes a very long time between needing sharpening. No doubt the very thin geometry contributes as others have noted.

Other well-regarded combinations in my mind: Birgersson + mystery Swedish steel, Kamon + 1.2xxx, Wakui + white 2. Although in the case of my Birgersson I’d say edge retention is as expected, long but not unusually long. The white 2 in my Wakui does last surprisingly long though.
 
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I also love AS but in this case I think the maker and specific knife matters as much as the steel. The Denka has the reputation of having amazing steel. By all accounts it’s a unique treatment (either heat treat or grind) that stands out from other makers’ knives with the same steel, which is what contributes to the TF cult.

Rather than focusing solely on the steel, you might want to focus on other highly regarded maker + steel combinations. Yoshikane SKD is an iconic combination, for example - and mine certainly goes a very long time between needing sharpening. No doubt the very thin geometry contributes as others have noted.

Other well-regarded combinations in my mind: Birgersson + mystery Swedish steel, Kamon + 1.2xxx, Wakui + white 2. Although in the case of my Birgersson I’d say edge retention is as expected, not unusually long. The white 2 in my Wakui does last surprisingly long though.
Birgersson steel is quite impressive for what I assume is still simple carbon steel, not Dalman HSS or ApexUltra but still quite long lasting
 
Birgersson steel is quite impressive for what I assume is still simple carbon steel, not Dalman HSS or ApexUltra but still quite long lasting

Agreed, I should edit my post to say Birgersson is very long lasting for a simple steel.

But my wakui white2 and yoshikane skd are unique in my collection as the only two that sometimes have me wondering, “why aren’t you dull yet?” But that’s relative of course, I have that thought about white 2 because it’s white 2, not because it lasts longer than something like apex ultra. Could be the grind on both too, as they’re both effectively lasers.
 
Wow, fun waking up to such a trove of information! I will need to read and re-read this to fully understand everything as there is a lot of technical information here, but at first glance my recommendation takeaway’s are:

Magnacut
Birgersson
Kamon
And I think ZDP something

Though I forget if that one was mentioned as being good or not good, I’ll double check.

Thank you again everyone and if there are any other recommendations or I have something wrong, please let me know!

With great appreciation,
Luke
 
Right away I just think of Mazaki and his white 2, it really change my perspective on steel and heat treating and real world results vs paper.

I find it interesting as it seems people talk about magnacut a lot but isn’t Apex ultra supposed to be a superior steel on paper?

My point of view is that my B1 knives can go months without sharpening, but the thing is I want to sharpen at the very least once every two-four weeks🤷🏻‍♂️

Super is going to last even longer than this, and it’s closer to 66+ while B1 is 64+ which the graph doesn’t show.

I will say that ApexUltra does seem to be a steel that stands out as it combines the properties of W1 with AS, both on paper and real life which is pretty amazing. It’s easy to sharpen, ultra hard, and ultra durable.

At some point the hardness just doesn’t matter anymore, however, other characteristics like durability and ease of sharpening, become incredibly relevant.
 
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