Naniwa Synthetic Ohmura #150

Review of the man-made replica



2/21/20225 min read

I've always wanted to give this one some heavy work outs knowing that it's a softer and very muddy stone. I realize this stone has been out for quite a while and I always felt that some tools (including sharpening stones) are time tested and still on the market for a reason. The Naniwa Ohmura, given its price point, was worth a try while saving the expense of long and demanding sessions on a true natural Ohmura sandstone. I love the Nubatama series for their ability to play well in transitioning from synthetics to natural stones. The handful of available synthetics created to mimic naturals in terms of feedback, slurry, and overall enjoyment; no matter how long they've been around are always worth some playtime. You never know what you'll like before you try it right?

I find having a great coarse stone is very useful for establishing a texture on blade roads that not only looks good, but is functional in the matter of food release and perceived drag through the ingredients while cutting or slicing. This stone, to my surprise, actually gives the user a wide range of control over the grinding power and finesse in shaping and finish. A very capable stone that Naniwa has nailed down given its focused spectrum of use (there's still limitations at the rated JIS 150 grit). I'm a fan of large stones. Bigger is better and the one I'm reviewing is the #1300 size LARGE Naniwa synthetic Ohmura. Let's get into this review about the stone that I should've tried long long ago.

An earthy smell hits the air as water seeps into this stone. It's absorbent and wicks in water very much the same as we see in natural stones; without the porosity of most coarse synthetic stones where water more or less runs straight through them. This Ohmura holds in water quite well, penetrates and saturates quickly; very much like a splash-and-go with no real need to soak. Although I do notice an increase in abrasive release when given some contact time, about 15 minutes either submerged or water resting upon the surface. One may ask, how can it be similar to splash and go when it draws in water? Well, just because it's coarse doesn't mean it is overly thirsty. I can immediately begin a session without distraction or interruption. Another bonus of not soaking a coarse stone! Once a few passes with a knife have been made, the way the mud hangs on the surface very much reminds me of arato aotoishi, only much more coarse. This stone actually plays a lot like the natural Ohmura coarse sandstones. The two don't quite sound the same but scratch the blade in a similar fashion.

When working on large blade roads, the Ohmura has several advantages and the quick buildup of mud is one of the nicest features to help with refinement of scratch depth whether left from the previous stone, or refinement of the Ohmura itself. It is so very helpful to have the versatility in a foundational stone especially one with such a coarse rating. This stone is comfortably soft and quickly conforms to the blade road. Water control is very forgiving even at the beginning of a sharpening session. While this stone cuts slow compared to the benchmark Nubatama 150, the versatility is the shining point of this stone which comes from mud control and proper sharpening pressure when refining scratch patterns. I can progress very comfortably to a 400 grit stone or even a 600 grit for further refinement. A jump to 1000 grit is possible with the right stone, but not recommended. I will also elaborate on the texture of blade roads from this Naniwa. It is indeed coarse but the scratches are mild and shallow. Fine enough to remedy the scratches left from an Atoma 140 grit diamond plate. The feel of the mud while the working the blade road has an almost powdery clay texture while water control maintains a creamy feeling without being overly 'gritty'. The finish left straight off the Ohmura is really not too bad. A natural stone finish from an aoto or similar Jnat is both eye catching and functional. The feedback working carbon steel on the Ohmura is fantastic and soft stainless cladding even plays well with the mud. The type of knives I disliked the most on this stone are higher hardness stainless alloy cores and like mono-steels. German knives are a breeze though thinning any stainless knife above 61HRC is slow and fatiguing. It technically can cut super steels however that's a no-go for me.

I wanted to use this stone dressed as a loaf shape. I've been wanting to do this with several pieces and this synthetic was the perfect candidate. I did not do this with the entire stone surface as I wanted the option to quickly convert it back to flat afterward. Finally after a few more months of use and I decided that I will keep one end as a loaf for inside/fine surface blade work. No regrets with this trial and happy to find another satisfaction in this (to me) economic category style of sharpening stone.

I have a positive impression of this stone after approximately 6 months of use. The knives I've tried so far range from SK-4 to Super Blue, Cutco to Ginsanko to R2, and many flavors in between them. The Naniwa Ohmura can't do it all with ease. Picking the right tool for the job is a significant element for many everyday tasks; over time this Ohmura has revealed what it can and can't do which makes stone selection easier knowing when to use it and almost more importantly when not to use it. Aside from the testing, when I choose this stone for tasks it's actually suited for, it is a very pleasing stone to use. Enjoyment factor and ease of use is a top notch value given this stone's price point. It definitely can not do it all. As long as the Ohmura is not forced to do something outside its abilities, I can confidently recommend this stone for both beginner and experienced sharpeners. If one seeks a harder or faster cutting stone I recommend looking to ceramic or diamond abrasive sharpening stones and there's many great and competitive choices. Naniwa Ohmura has many commonalities with the Naniwa Aotoshi Green Brick of Joy. If you would want to try a Green Brick in a 200 grit feel, this Grey Brick is worth a look.

Thanks for checking it out!