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Nubatama Ume 2k - Olive brick of Joy :)

Fri Aug 03, 2012 5:58 pm

Nubatama Ume 2000 grit Waterstone: First Impressions part 1 of 2

I will be reviewing the 2000 grit Nubatama Ume waterstone, one of the latest additions to the Nubatama collection. It is olive or khaki colored, an 'Olive brick of Joy' :)

First impressions (dry) is a very silky smooth, reminiscent of some of the Naniwa stones.

Water absorption - not that porous, essentially a 'splash and go' stone even just misting rather than soaking the stone. I soak it for a moment while discussing some topics.

Why a 2k in general? I feel that between a 1k and 5k, the 2k gives a few advantages. Excellent for touchups where it is unnecessary to go down to to a coarser 1k stone. Also a good intermediary when abrading harder steels. Also for many purposes an excellent final edge when compared to a 1k edge. This stone because of its size should also work well as a superior stone substituting for the 1500 King stone commonly found in Sushi bars as a house stone. The 2k stone also reduces the wear on your more expensive finer grit stone.

Why did I bring in another 2k stone? We have the exceptional 2k Bamboo stone - but it is a more exotic and expensive stone and I wanted something more general purpose and affordable.

I test with a variety of knives in this video: a Sugimoto White steel short cleaver the size of a nakiri but more heavy duty - very handy knife. Next is a Misono Hankotsu - flat on one side and convex ground on the other. Finally a 330 mm Tojiro Gyuto, a stainless steel.

I demonstrate with the cleaver how to determine the existing angle with an edge leading stroke, feeling when the stone 'grabs' the edge 5:28. A very smooth stone.

I comment on not flattening stones in these videos initially - first because these are 'first impression' videos, second because I wish to demonstrate initial porosity and soaking times and third because the stone come out of the box quite flat already. I would certainly not object to anyone flattening these - or any brand or type of stone initially. Flat is always good.

I comment on controlling water volume on the surface of the stone to control and maximize grit density. Note me 'pushing' excess water off the top of the stone 5:44 to reduce water volume, allowing me to obtain a higher grit density sooner, since this stone absorbs water slowly.

The stone does generate a small amount of mud, to be used to advantage. It is a very pleasurable stone to use. The stone is medium hard to soft. When wet it becomes a darker olive or Khaki green color. Rather than waste mud, I wipe it off the blade and put it back on the stone. Brings the knife from slice cut only to ~ 1inch out push cutting. A moderate mirror finish.

Next the hankotsu - a heavy short knife used for a hanging style of butchery. I also use it as a steak knife and this does dull the edge more quickly, which is why the knife requires sharpening. Initially the knife will barely slice cut paper. The back is sharpened just barely less acute than lying it flat against the stone. Using the mud generated from the first knife lets you get a smoother feel. You can cut into the stone on edge leading strokes if you are too sloppy in your control of knife angles. Note that when you feel the knife digging in a bit on edge leading strokes that this more rapidly increases the mud density, adding stone particles to the slurry. I do catch the stone a bit 15:29 in a sloppy stroke, something I have done on the Naniwa green brick stone too. A bit more time on the stone shows improved cutting performance, with excellent slice cutting and close in push cutting.

I also demonstrate stropping on a piece of paper. This should be done with better support of the paper. The finish produced is an appropriate final finish for the intended use of this knife.

Next the 330mm Tojiro DP knife, an HRC ~ 61 stainless VG10 type steel in need of a touchup. I discuss sweeps, fully utilizing the full length of the knife reducing flattening requirements. I also discuss edge trailing only pushing water towards one end of the stone. These long knives I find useful for initial prep of food, breaking down multiple pieces of produce - watermelon, bunches of food etc.

I also demonstrate sweeps keeping the guiding fingers over the stone as the blade sweeps beneath the fingers, sectional sharpening and 'w' strokes, linking a series of partial sweeps together.

I use these highly water absorbent towels - used typically for car washing - available at Costco or automotive stores. A well dried knife gives you MUCH more accurate sharpness testing, since any moisture will decrease performance of sharpness testing - wet paper is useless for testing and a knife retaining moisture won't cut as well. Worth the small extra effort.

The finish on the edge is a slightly matted mirror finish. Edge testing is incomplete and continued on another short video.

http://www.youtube.com/watch?v=S4Yz0eco ... e=youtu.be

This short video is cutting testing after further refinement of the edge from the previous video. The cutting tests at the end of the previous video did not reflect the true performance potential of the stone and were, in retrospect premature testing of the incompletely refined edge. Note in particular the increased push cutting performance.

This short video is cutting testing after further refinement of the edge from the previous video. The cutting tests at the end of the previous video did not reflect the true performance potential of the stone and were, in retrospect premature testing of the incompletely refined edge. Note in particular the increased push cutting performance.

Available at Chefknivestogo:


Re: Nubatama Ume 2k - Olive brick of Joy :)

Thu Jan 22, 2015 7:34 am

um, where did this stone go? and how does it actually stand opp to the green brick?

Re: Nubatama Ume 2k - Olive brick of Joy :)

Thu Jan 22, 2015 9:03 am

Ken stocks them at Precise Sharpening, they are available through him. Or I should say, they were available through him as recently as several months ago.

I have no personal experience with the stone to offer, sorry.

Re: Nubatama Ume 2k - Olive brick of Joy :)

Thu Jan 22, 2015 9:36 am

Thank you, Dan for mentioning this. I do still carry the FULL line of Nubatamas, including the 2k Olive Brick of joy. I will continue to support the full line of Nubatamas, rather than any subset that a particular vendor carries. I am actually expanding the line when I see reasons to expand it to meet specific customer's needs. This includes another 2k and 3k stone in addition to the existing three 2k stones. Rather than concentrating on multiple lines, Nubatama's philosophy is to have a single and diverse range of stones to meet the needs of experts and beginners alike.

I of course like the stone. Melampus has one and likes it a lot. Perhaps he will see this.

ShinOokami, send me a PM and I can go over it in detail, comparing it to other Nubatamas and other stones as well.


Re: Nubatama Ume 2k - Olive brick of Joy :)

Fri Jan 23, 2015 8:34 pm

I stopped by Ken's place today and the new Nubatama 3K stone is now a great addition to my collection.

I brought some chisels and knives to Ken's today to try some stones not in my current lineup and I came away with a new 150 grit Nubatama and a 1K Nubatama which are great performers.

I spent a few hours trying out different stones and I thought with the number and variety of stones in my inventory I would just visit but, since I brought my stones with me for comparison I now have a few "upgrades".


Re: Nubatama Ume 2k - Olive brick of Joy :)

Sat Jan 24, 2015 1:13 am

Olive brick of Joy......what an original name.

Re: Nubatama Ume 2k - Olive brick of Joy :)

Sat Jan 24, 2015 7:37 am

Jack09> Which 1K did you get and why?


Re: Nubatama Ume 2k - Olive brick of Joy :)

Sat Jan 24, 2015 9:21 am

I opened this thread because I am interested in adding a synthetic auto and thought this might be relevant to my search. Instead I find a reposting of an old advertisement for the stone complete with an expired link. What is the point? Even used car dealers update their ads occasionally.

Re: Nubatama Ume 2k - Olive brick of Joy :)

Sat Jan 24, 2015 11:09 am

I'll respond in reverse order to the postings.

Craig, the posting you refer to was made in 8/3/12 so that it hasn't been modified isn't really surprising. I don't tend to revise old postings I've made as this is something I would consider devious. I leave what I've written at the time as they stand. Posts about other products in the Nubatama lineup - or any products for that matter don't self update. I may have to reconsider this personal policy to at least update the copy on the videos as availability of a product changes. The information copied here is directly the same information in the information contained in the youtube commentary for that product. Remember that this series of videos are my first impressions of a stone, something I cannot duplicate. I think the sarcasm is unwarranted, but appreciate you bringing this to my attention.

Douglas, the 1k Jack mentioned was the 1k Speckled Ume in the XX Hard formulation. He brought is over with him to use as part of the sequence. IMO this stone fits his needs for chisels very well, because, unlike knives, you are working a large surface for a longer period of time to produce a flat surface with higher requirements for fltness than a double or even single bevel knife. I particularly like the XX Hard formulation for use on the EP and woodworking applications.

I will add that I was quite impressed with Jack's depth of knowledge and discerning taste, both in woodworking and metallography. I learned a great deal from his visit about wood and woodworking tools and look forward to more in the future. Thank you, Jack.

Jeff, yes the name is an obvious play on words as both stones are 2k stones and I did compare my impressions of the stone to the Green brick of Joy in the video, since it is a popular stone many people are familiar with.

Jack and I had a really good session. This session was my first time getting and using this new 3k Ume stone. Both of us were impressed with the stone. We used the stone as a 'bridge' between the 1k XX Hard speckled Ume and a Shapton pro 5k stone. We also used it to remove some microchipping and establish a more precise edge on a gyuto (white steel I believe). Briefly here's my (first) impressions of the stone.

It (3k ume) absorbs water fairly slowly requiring a couple minutes of water under a tap or soaking to saturate. After that not much more water needs to be added so it is about as 'splash and go' as say a Chocera 3k, but not as splash and go as a Shapton Pro. It is a fast cutter at 3k and immediately generated jet black mud that becomes a gray slurry on the stone's surface. It is significantly less prone to glazing than the Glassstones. The level of feedback is quite high, moreso than both the Shaptons and Choceras, yet not annoyingly so, reducing a bit as you develop some mud. The scratch pattern is appropriate for a 3k level of finish and the jump to a 5k Pro stone was an easy jump. Also a similarly easy jump from the 1k XX Hard. Wear rate is quite low, so it maintains flatness even when used for longer sessions required on a chisel back which has much greater surface area than say a gyuto. Because it does generate some mud, I find this a more suitable stone for use on a single bevel knife as well as a double bevel knife. Using this stone on the gyuto next, it quickly got rid of microchipping, attesting to it's speed at a 3k level of finish. I followed this stone with a Yaginoshima Asagi as a final finisher for the knife. The jump was very reasonable and left an excellent edge on the blade. If you are using a synthetic stone as a midgrit or nakado level of finish before preceding to a finer level of finish instead of a synthetic aoto for instance (reverting to the OT) this will work quite nicely for this application. It is a harder stone than both synthetic 'aotos' and most natural stone 'aotos', with there being some hard [natural] aotos as exceptions.

The Nubatama line currently only has one 3k stone - the 3k Bamboo. While it is an excellent stone, it is pricey and best suited to a serious sharpener for use with naturals and maintaining a kasumi finish. IMO this new 3k Ume is a much more affordable alternative for most applications, fills a 'gap' in the Nubatama lineup and is a strong competitor for a 3k stone in anyone's stone selection choices.

Jack, I hope you enjoy your new stone. I also have this stone cut for the EP, so EP users can also enjoy using this newest member of the Nubatama lineup.


The 150 Bamboo worked out well for Jack's application. It maintained flatness quite well for the application and quickly converted the scratch pattern and produced a flat back surface. He was looking for something other than the 140 Atoma which he felt left scratches that were too deep. We tried a 320 bamboo stone, but in the end Jack didn't feel that the overlap for these stones offered enough differentiation for his tasks vs his Shapton Pro 320 to justify it's purchase.

Re: Nubatama Ume 2k - Olive brick of Joy :)

Sat Jan 24, 2015 11:28 am

Douglas -

My first 1K stone was a Bester which cut ok but, I hated soaking so long since I sharpen in my wood shop. I upgraded to the Shapton Glass 1K which is an improvement as it's a splash and go stone but it seems to load up pretty quickly (I'm removing a lot of metal flattening chisel backs, etc). Then I bought the Nubatama Ume 1K xxhard stone and for a woodworker it's the ideal stone. It cuts very fast, stays flat a long time, doesn't clog and you don't have to worry about the edge digging into the stone. I also bought the forum special last month the Suehiro Cerax 320, 1K and 6K to give them a try but, the 1K and 6K perform the same as my Shapton Glass (which also load up too fast).

As I was in the process of posting this I got the message that there was another post so I read Ken's response first. As Ken mentioned I purchased the 150 grit Bamboo stone to work out the manufactures grinding pattern and this is the best stone I've ever used for that purpose. Since I work mostly with very hard and dense woods chopping mortises sometimes results in large chipped edges or broken corners on the leading tip of the chisel. Previously I've used my 3M diamond plate and more recently my Atoma 140 but I think the 150 bamboo will fit in very nicely.

I also had a difficult time going from the 1K Ume xxhard stone to my Shapton Pro 5K or any of my 6K stones. When I say difficult time I mean by the time I eliminate the scratch pattern of the 1K stone the 5K stones dish just enough that the back of the chisel is not quite flat across the leading edge. The 3K Ume stone is now my 2nd favorite stone after the 1K xxhard Ume since it cuts so quick and stays flat allowing the transition from 1K to 5K or 6K to be accomplished in a fraction of the time.

I'm not sure about the knife sharpening community since my knife sharpening skills are still evolving but, for the woodworking community these stones will be a giant hit. I belong to a few woodworking forums including the FineWoodworking (paid membership) and will be doing a review soon. I'd expect these stones to be out of stock real soon.

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