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spaceconvoy
09-01-2013, 06:33 PM
Just received a JNS 800 Matukusuyama from Maxim's discount sale, couldn't resist jumping on such a sweet deal.

First thing I noticed while soaking, bubbles were pouring out from the kanji, but seemingly nowhere else (photo 1). Very weird, but soon I found out why...

This is a very crusty stone. For the initial flattening, drywall screen didn't work on it at all. On a whim, I tried it directly on the marble tile I bought from Home Depot to use as a reference plate. The unpolished backside has a saw-mark pattern that feels kind of toothy (photo 2). Surprised it worked, but took some time to wipe out the penciled x I had drawn... and it still wasn't good enough. I had to keep flattening until the kanji was almost gone to finally get to the good stuff.

After the crust's gone, now the drywall screen does sort of work for flattening, but it's still really slow. Seems like a very slow wearing stone, even after making a bunch of mud.

It's a harder than average stone, but still has excellent feedback. Sharpening the thin bevel of a gyuto, it doesn't raise any mud, and the surface feels more grippy and gecko-foot-like than other stones. Reminds me of my old Sigma Power 1k hard type in this respect, but not quite as hard or fast. I would call it a fast stone, definitely faster than the Arashiyama 1k or Red Brick, but not super fast.

The surprising part is the mud it makes on wide bevels - I tried thinning my Artifex since I don't own any single bevels. The great thing about this mud is it seems to continuously refresh itself, staying relatively thin and maintaining the right water-content to keep things lubricated. Other muddy stones I've tried keep raising mud while getting drier and drier, eventually gumming up into a sticky mess. This feels like magic mud.

Check out the dots that look like stray grit in the 4th photo, they're actually tiny bubbles coming up the surface - I suspect this is why the mud stays nice and workable, and why it should be soaked for as long as possible.

And the finish is really nice, hazy and dark grey. I can see how this would be amazing for doing kasumi (photos 5&6 - ignore the low spot near the edge, or blame Mark Richmond :D )

Overall, the JNS 800 feels like an ideal compromise stone to me. It's like you're getting two stones, one that's relatively hard and fast with good feedback for cutting bevels, and another that makes excellent mud and creates a hazy finish on wide bevels. It hardly dishes but requires a long soak, a tradeoff I'm more than willing to make. Seems like a keeper.

http://i695.photobucket.com/albums/vv319/spaceconvoy/DSC_8865.jpg

http://i695.photobucket.com/albums/vv319/spaceconvoy/DSC_8868.jpg
Back of the marble tile I used for flattening

http://i695.photobucket.com/albums/vv319/spaceconvoy/DSC_8871.jpg

http://i695.photobucket.com/albums/vv319/spaceconvoy/DSC_8873.jpg
Tiny bubbles

http://i695.photobucket.com/albums/vv319/spaceconvoy/DSC_8877.jpg

http://i695.photobucket.com/albums/vv319/spaceconvoy/DSC_8889.jpg

wsfarrell
09-01-2013, 06:45 PM
Definitely a keeper. I flattened with an Atoma 400, didn't have any problems. I've used it on several single bevels, and it pretty much eliminates the need for fingerstones to even out the bevel.

Easily the most versatile 800-1200 stone I've ever used.

spaceconvoy
09-05-2013, 05:22 PM
Versatile is definitely a good word for it.

I spent about an hour over the last few days flattening my Artifex on it (probably a waste of a good stone), so I have a few more things to say... I'm now even more impressed at how little this stone dishes considering the mud it makes. Still a complete PITA to flatten with drywall screen

And while it cuts just as well with a short soak, to get the best mud it really needs to soak for a looong time. At 4 hours the mud was drying out a bit and it didn't seem as saturated as it could be. At 8 hours it was golden. I left it soaking overnight, and the next day it seemed imperceptibly better, but it was probably my imagination.

Another good word for it is balanced. For me it's the perfect combination of hard, muddy, fast cutting and slow wearing with great feedback.

Talim
09-08-2013, 02:15 AM
I just used this today for the first time and although I'm still very new to sharpening, I was still very impressed by this stone. I only soaked mine for 30 min before use and used it to thin a Tanaka ginsanko petty. I first used a beston 500 and then the jns 800. Beston was of course very gritty but the jns 800 was very very smooth. Smoother than Bester 1200 I think and I just love the mud it created. It indeed felt like magic mud. I must have used it for good 20-30 minutes and hardly dished at all. I still have to work on my thinning so I can't really say anything about the finish just yet. This stone is a real steal at the sale price and would gladly pay for it full price.