Disclosure: This is the same Sage 6 REX 121 as my last review, only one week later, provided by Spyderco as a complimentary review sample through the Spyderco Ambassador Program. Receiving this amazing knife does not influence my opinions. Spyderco does not preview, edit, or approve my reviews, and all conclusions are based solely on my own testing and experience.

I call this Sage 6 “Tango”.

Why Tango? Because orange is the color that immediately comes to mind when I look at it — and because the name evokes the Argentine tango dancers of the early 20th century, with their flamboyant, warm-colored clothing.

So, for the rest of this review, Tango it is.

And this particular knife is about to take us somewhere rather unusual: into the world of REX 121, one of the most extreme cutting steels I have ever had the pleasure — and sometimes the frustration — of using.

The Sage 6 Rex121 is not without its flaws. Like every Sage I’ve used, the quillon at the choil is just a little too sharp for my index finger.

The idea was simple: just knock the edge down a bit with a diamond file.
Well, it’s moments like this that make you realize just what a fucking bastard of a steel REX 121 is to file!! Pardon my French.

And on that note, I still haven’t achieved the convex edge I ultimately want.
One thing is certain: REX 121, with its huge percentage of tungsten and cobalt, responds politely only to diamond.

As I’m rather clumsy, I use gaffer tape to protect my blade’sides from scratches I might otherwise cause. Diamonds are unforgiving.
And remember I don’t really sharpen; I reshape that edge, rounding off the angle and turning the original bevel into something more convex and organic — and, above all, much easier to maintain freehand.

The result is immediately apparent in my test, where I push-cut through the bottom of a Coca-Cola plastic bottle. The plastic is thickest right in the center of the bottle’s base, where it corresponds to the injection gate used to form the bottle.

Straight out of the box, Tango couldn’t cut through it.
Once I had convexed the edge, however, the blade went through it with ease.
(But when it comes to this particular test, the Nilakka by Pekka Tuominen wins every single time as also Opinel’s thin blades…)

Naturally, I’ve cut a lot of cardboard with it.

That’s probably the one area where REX 121 absolutely makes a mockery of every other steel on the market, treating them all like a bunch of under-carbonized losers.

I used a Triangle Sharpener with CBN rods, setting the edge at 15° per side.

Once I had established a good edge, I went straight to the leather strop.

The result is a rough shaver, but a shaver nonetheless. It has plenty of bite.

Now, this big show-off of Tango has also been put to work on much more mundane tasks.

Now you’re going to tell me that a 440A knife would handle sausage meat or bread perfectly well, and I’ll tell you that you’re absolutely right.

But this blog isn’t called Nemo Steel Review, is it?

And so that very Sage 6 gets exposed to grease and crumbs.

Those two organic contaminants, once they make their way into the mechanism, can become a problem…

And things could get even worse when you’re skinning a hare…

I don’t have those kinds of thoughts when I use my Manix MagnaMax, fitted with the handle from my Manix 2 Salt, because I know I can soak the knife in hot, soapy water without worrying about corrosion.

But with a Sage 6 carrying a steel this extreme?

Is it going to start rusting somewhere I can’t see?

And will those uncoated skeletonized liners eventually turn into little pockets of rust? Or bacteria colonies ?…

My first thought was to apply a thin layer of Teflon-based bicycle chain oil inside the handle, using a cotton swab soaked in it.

Then I thought: am I really going to have to do this every single time I use it ?

Why the hell am I putting myself through this when I have…

Its little brother, the Sage 5 Salt Lightweight with its CPM MagnaCut blade.
A pure masterpiece of an EDC knife, with every metal component built to withstand a dip in the ocean. Its review is here BTW.

The kind of knife you can throw into the bottom of your suitcase before taking off for some unknown destination. It’ll survive a stint in the rainforest or a picnic beside a salt lake without batting its spyderhole of an eye.

The Sage 6 REX 121 and the Sage 5 Salt MagnaCut represent two almost opposite philosophies of EDC knife.

The REX 121 is a cutting machine: its extreme wear resistance gives it phenomenal edge retention, especially when cutting cardboard.

The trade-off is an exceptionally demanding steel to sharpen, with far less tolerance for moisture and corrosion.

The Sage 5 Salt takes a completely different approach: MagnaCut offers an outstanding balance of edge retention, toughness, and exceptional corrosion resistance.
And the Salt takes that philosophy all the way.

The Sage 6 is the one I’d choose when I want to push cutting performance to the limit, while the Sage 5 is the one I’d take anywhere without having to worry about maintenance.

One makes you think about its steel; the other simply lets you use your knife.

And that, ultimately, is the difference between an extraordinary specialist blade and a true adventure EDC.

I also managed to get a really nice convex edge on my Sage 5, and at this point it needs nothing more than a strop to keep it sharp. It’s a whittling champion, whereas the Sage 6 still needs some work to refine its edge.

MagnaCut is also remarkably tough, while REX 121 is considerably less so. That difference in toughness is something you can feel in actual use: MagnaCut will be much more forgiving when the blade encounters twisting, knots, or lateral stress.

In short, comparing these two brothers is genuinely fascinating.

And I have to admit, choosing REX 121 could almost be considered a form of masochism: it’s more demanding to maintain, both when it comes to mechanism and edge.

But there’s something intoxicating about using REX 121. Putting a steel of this caliber into such an “approachable” friendly platform as the Sage 6 is an experience you really have to live through.

It’s like having a lion in your pocket, ready to roar — to borrow Prince’s words from 1999.

So, ten days later, where does that leave the Sage 6 REX 121?Somewhere between a brilliant EDC knife and a beautifully unnecessary piece of madness.

The REX 121 is an extraordinary steel, but it comes with a price: sharpening is a pain in the arsenal (!!), corrosion resistance requires attention, the edge is less forgiving, and even the mechanism makes you think twice about what you’re putting this knife through.
(The Sage 5 Salt MagnaCut is, in many ways, the rational choice. It is tougher, vastly more corrosion resistant, easier to maintain, and an outstanding whittling knife.)

And yet, if you ask me which one I find more exciting to use, the answer is the Sage 6.

There is something deeply satisfying about having a steel this extreme on such an elegant, compact and friendly platform. It makes very little practical sense — and that is precisely what makes it so much fun.

The Sage 6 REX 121 is not the knife I would recommend to someone looking for the easiest EDC life. It is the knife I would recommend to someone who wants to experience what happens when you put one of the most extreme cutting steels available into one of Spyderco’s most refined platforms.

And if this review occasionally wandered a little too far down the rabbit hole, well…

“I was dreamin’ when I wrote this. Forgive me if it goes astray...”

After all, this is a knife made from REX 121. A little madness was probably unavoidable.