I've not seen anything written up on the newly released CKTG Nubatama stone set and given that it breaks with convention in the 150 to 1K jump, I though I'd do a quick write up on my experience with it.
For reference, I have other stones to compare the set to including the DMT XXC, DMT XC, Bamboo 400, Latte 400, King 800, King 1K, Bestor 1.2k, Rika 5K, King 6k, and the Arashiyama 6k. On the natural stone side, I have an Aono Aoto ( 1000 ish ) and a Meara ( 5K ish ).
I've used all these stones to sharpen knives including White #1, Super Aogami, and German steel.
While I do trust Ken and Mark, I did come at this with a bit of a prejudice. Nothing I've read suggests a 1K stone can in a timely manner deal with a 150 scratch pattern. I know any 1K can grind out a 150 scratch pattern given enough time and determination, but a good fit? I was doubtful.
The 1K to 5K jump I was fine with. For the most part, I do my daily sharpening in the 1K range and jump to the 5K range to finish.
With that as background.
The premiss behind the Nubatama CKTG set is speed. The idea is that the 150 is faster than a 400 but smooth enough that a good 1K can deal with it effectively.
I got out a white steel Goko Gyuto and set the bevel with a Bamboo 400 to get a reference, and re set it with the Latte 400.
Next I reset it with the 150.
Okay, the 150 is WAY faster then both the 400's. I can imagine if the knife had any damage like chips or needed a reprofile, there would be a lot of time saved using the 150 compared to the 400's.
So as far as that portion of the premiss, we are in good shape. How about how long it takes for the 1K Ume to get the 150 scratch pattern out? I'm thinking I better go get a cup of coffee and turn the TV on.
I start on the 1K and checked after a hand full of fore and aft strokes. Damn, the 150 scratch pattern was really eaten into. So I go another hand full and its done.
I do the 400 / Bestor 1.2K progression all the time when I polish blades and I really don't feel that the Nubatama 150 / Ume 1K takes anything but a few strokes longer. The Ume 1K is a beast. Anyways, unless the 5K is a complete dog, at this point, I am thinking from the point of view of speed, assuming you are using the low grit stone for a reason, i.e. damage repair, the 150 / Ume 1k / 5K is a winning combination.
And as it turns out, the 5K is not a dog. This is definitely an awesome set speed wise.
To extend this post on a little, a few general observations about these stones......
Its a big stone in that its much taller than a standard cut.
Very dish resistant.
Better feedback than the DMT XXC.
It makes no mud.
It needs a 10 minute soak to retain a moist surface. This is getting better with time. When I first got it, it took about 20 minutes.
It's scratch pattern is much finer than the DMT XXC.
It's scratch pattern is no where near as fine as the scratch pattern of the Latte 400 or Bamboo 400.
Uma 1K speckled medium:
Standard size stone.
Medium hard. Similar to a Bestor 1.2k
Very dish resistant.
Feels good to use, much like the Bestor.
Makes very little mud ( will make mud with a slurry stone )
Splash and go.
The edge it leaves is a little more complex than I am comfortable describing. It definitely feels different than the edge of the other synthetic 1K stones I have. I want to say more like a natural. But I've also read somewhere that it does so am wondering if my perception is being altered by what I read. I have a USB microscope coming so will be able to quantify this better in a few days.
Standard sized stone.
Very dish resistant.
Feels not unlike the Arashiyama 6k, i.e silky, but where the Arashiyamas feel quickly changes as it produces mud, the Bamboo being a lot less muddy doesn't.
Very little mud.
Splash and go.
The edge refinement is definitely a lot closer to the Arashiyama 6k and King 6k as opposed to the Rika 5K which unless you muddy it up and work it, is much more like a 3K.
Some random thoughts.
My general sharpening progression, assuming no edge damage has been the Aoto Aono to a Meara, both naturals. They both feel great and are splash and go's which I really like.
If the blade has some light damage, I tended to go to the Bestor, then the Aoto, then Meara.
I'm definitely going to replace the Bestor in the progression with the Ume 1K. While I REALLY like the Bestor, the soak time is a downer for me. I don't want to permasoak the stones. The Ume feels great, is as fast or faster, dishes less, no soak, and has a really interesting edge.
Would I skip the 400 and go straight to the 150? No.
No point given I have the 400's especially considering the Bamboo 400 is a splash and go where the 150 isnt.
If I could only have one, a 400 or a 150, which would I get?
If I had a Ume 1K, I'd go 150 because its just so friggen fast compared to a 400, and if I was dipping down to the low grits, the assumption is that there is something messed up to fix.
On the other hand, if I had a slow 1K ish stone like the King or Aoto, I would go 400. I tried the King and the Aoto against the 150 and it was a bit of a snooze fest.
Would I replace the Aono Aoto with the Ume 1K?
Ha, that is a hard question. The Ume is a really nice stone to use and while I like the Aoto a lot, I am not totally sold on muddy stones. I think I'll swap them against each other for a while and see where I end up.
Would I replace the Meara with the Bamboo 5K?
No. Its not that there is anything wrong with the Bamboo 5k, its an awesome stone, but I prefer the Natural as a finisher.... at the moment.
If I did not have the Meara, which synthetic would I choose?
Would be a tossup between the Reka 5K and Bamboo 5K.
The Arashiyama 6k and King 6k are both atleast 6K grit stones with some saying the Arashiyama 6k is closer to 8K.
I like a little bite in my edge. I tend to use the finishing stones more like strops then sharpening stones so when I get to 6K and 8K edges, its going a bit far for me.
The Rika is more like a 3K stone than a 5K, where relative to the others, the Bamboo 5K feels like a 5K.
I am thinking I would use the Rika on a blade for veg, and the Bamboo on a blade for protein. Hows that for a cop out