Three popular 1000 grit stones: King Hyper 1000, JNS 1000, and AI 1000 (Watanabe)

This is a brief comparison of three popular 1000 grit stones (JNS, AI, and King Hyper standard). The criteria used to compare the three stones are some of the characteristics that define a good or bad whetstone. Keep in mind that much of this is subjective and that no rigorous scientific experiments have be done to compare these stones . I’ll try to give each stones a 1-10 mark with 10 being the best and 1 the worst but this is very subjective and dependent on every person’s reference point so bear that in mind. Also, these ratings are only compared to the other 1k stones tested, and cannot be used to compare these stones with stones that have a different purpose (e.g. polishing stones).

This review is written by Carlos (KKF handle: valgard)

Splash or soak – The JNS and AI are splash and go stones, very convenient for traveling or at home. The King Hyper is a soaker stone, it holds water very well once soaked but it does need a good 40 minutes soak to work properly if it’s completely dry.  The positive about the King Hyper is that it can be permanently soaked so if you have the space to keep it soaking it’s ready to go at any time. An idea here, you can keep your soaker stones in the water tank of your toilet.

The speed – Here the AI takes the cake with ease, the Hyper is rather not terribly behind and these two are probably two of the fastest 1K stones out there. The JNS stone is still fast but it is a substantial drop off in speed from the other two.

AI 10

Hyper 8.5


Feedback – The King Hyper has the nicest feedback by far, very pleasant to use, feels almost creamy but it also tells you it’s removing metal fast. Then comes the JNS, feedback isn’t as nice, feels harder and glassier, but gets better once some slurry builds up, still not a super pleasant feedback. The AI has pretty crappy feedback in my opinion, it feels like a much coarser stone (I think it actually is coarser), a bit sandy, very hard, but you know it’s eating metal from what you feel and see.

AI 5

Hyper 9


Dishing and clogging – The AI and JNS are pretty hard and dish resistant (for a 1K synthetic stone), which is a big plus to me since flatness of the stones is a big concern, when polishing a hard and not very muddy stone at lower grits is also very useful to evaluate progress correctly. The King Hyper’s biggest weakness might be here, it dishes pretty fast, going out of flat rather quickly. JNS can clog a little bit but it’s not a big issue.

AI 8

Hyper 6


Finish and edge – Finish is very nice off the Hyper and JNS stones! It is probably the easiest to achieve a nice finish from the Hyper and it provides more contrast than the other two stones, but it does seem to hide some scratches which can be problematic when moving up to higher grits. The JNS is very consistent and seems to scratch slightly less deep than the AI, which actually is very valuable when moving up in grit. The finish of the AI is rather consistent but scratches are very deep and ugly finish, definitely looks like a coarser than 1K finish. I tend to use the AI followed by one of the other two stones before moving up in grit.

I don’t normally finish edges at 1K except cheap stainless, the King Hyper leaves a pretty good edge and it’s easier to reduce the burr on this stone than the AI. Haven’t really used the JNS to finish any edges yet.

AI 5

Hyper 9

JNS 8.5

The price – The prices for AI and JNS are fixed, the Hyper will depend on your location and where you can source it from, I got mine off eBay for about $55 USD. Here the Hyper wins but it isn’t a truly significant difference given that most sources have it around $65 USD. Shipping from JNS if you get it together with some other products might be free (my case), and from Watanabe is EMS so that puts AI probably as the most expensive. In any case, there’s not a huge difference among these in terms of price and it shouldn’t be a major consideration when choosing.

AI ~$70

JNS  ~$70

Hyper ~$55

EDIT: a note here that might be relevant depending on the region you live in, the AI 1000 is the same as the Sharpton Pro 1000. Thanks to Matus from KKF for confirming this.

Conclusion – All in all I think the JNS might be my favourite all around as it scores pretty consistently on all tests, and would be my choice if I could only have one 1k stone. The AI is the best for heavy scratch removing and can even be used for light thinning, the Hyper is great for pure sharpening or for leaving a nice finish and has the most pleasant feedback. All three are great choices in the 1K range depending on your preferences.

 King Hyper 1k (standard)JNS 1kAI 1000
Dishing and clogging688
Finish and edge98.55
Average rating87.57

Disclaimer – I wasn’t sponsored by any of the sellers or makers of these stones in any shape or form. Images are taken from JNS, Watanabe and an unknown source (in case of the King hyper).

This review is written by Carlos (KKF handle: valgard)


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