Hello everyone.

I recently purchased some slate and shell go stones with bowls on Ebay and I was wondering if anyone might be able to tell me more about them. I've seen some other posts of a similar nature and people being able to determine the difference between Japanese and Mexican shell stones or what kind of wood bowls are made out of.

I have no idea what the age of these stones are, but I'd be curious to get some opinions from those that are more familiar. As far as measurements go the shell stones are ~21.95mm x ~6mm and the slate are ~22.04mm x ~6.23mm. So far I've washed the shell stones with soapy water and they appear to be pretty white, would a H2O2 soak whiten them up even more?

I'd also be curious about the bowls too if anyone has any ideas about them, possible age or type of wood?

The file upload here was giving me trouble so I uploaded pictures to Imgur:
https://imgur.com/a/mBxLX


Thanks!

Hi Traveler,

Congrats on your new set.

About H₂O₂, one idea: pick one of the shell stones that you find still "stained", take high quality photos of its "stains", and try it with a small amount of H₂O₂. Compare the before and after. This way, if the chemical does any damage, it's limited to only one particularly "stained" stone, and not your rest. Conversely, if it does reduce the stainness with no obvious damage, then you can try it on a few more other shell stones.

I like your use of a caliper.

Nice stones.

Slightly unusual: the shell stones look like a mix of grades. Some have striations that are close together and regular, and some are far apart or irregular. Maybe this was the norm years ago?

Your slate stones need a few drops of mineral oil or a wipe with a mineral oil dabbed cloth.

The bowls look like chestnut to me.

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Thank you. They were less than $100 shipped from Japan so I think I got a pretty solid deal on them.

The shell stones definitely vary. Some don't have any visible striations, while others have quite a few. Some even have them front and back. I took a light to them all and they are all shell though. Kind of interesting.

Yep, washing the slate stones and oiling them was going to be a tonight project.

Nice stones

Re: Cleaning: I recommend reading How to Clean Slate and Shell Go Stones by L19 forum user “Erythen”, he has quite some experience with refurbishing used Go stones (as you can see if you read his posts here).

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Thanks for that. That's actually the guide I have been following. Very good instructions.

The bowls are certainly chestnut, an inexpensive type of wood. I wouldn't venture to say definitely about the stones. My guess would be Mexican clam and varying grade. Are the stones of different thicknesses, too?

Thanks for the reply gowan.

The thickness of the stones is pretty consistent.

The stones are Mexican clamshell and Jitsuyo (Standard/Practical) Grade. Just looking at them I'd guess they were size 22, or maybe 25. I couldn't say for sure without a caliper. For reference size 20 is 6.0 mm, size 22 is 6.5 mm, and size 25 is 7.0 mm.

H2O2 would probably clean them up a little...hard to tell since the pictures are dark, but if you feel it's worth a try then I'd say go for it.

I hope my guide helps

Now the bowls really catch my interest. The wood is Chestnut so pretty standard and inexpensive, but I love the gorgeous carving on the bottom. Very unusual and quite beautiful...if they'd ended up in my hands I'd keep them in my little personal collection . Please treasure them for many years to come

Thanks for the reply Erythen.

How can you differentiate between Mexican and Japanese clam shell? I've tried finding picture comparisons, but have been unsuccessful. I figured they were Mexican clam shell though.

They are about 6 mm, little bit of variation, so size 20.

Your guide is very helpful and clear, definitely appreciate you creating it.

I'm pretty happy with the bowls. From the pictures on Ebay I thought they were just scratches from age so the etchings were a pleasant surprise when they finally arrived.

There's often a little difference in size between the stones. Size 20 shell stones are basically anything from 6.0 mm - 6.4 mm. It allows some variation between stones in the manufacturing process. As a normal rule, however, the slate will be one size larger than the shell stones in order to balance the illusion of the slate being smaller on the board.



This an get a little tricky, but once you've had a little practice with what to look for it's fairly easy to spot the difference.

Mexican stones are graded on where the stone is cut in the shell (basically the fineness and uniformity of the grain).

Near the base you'll get snow grade which has a fine, fairly uniform grain. About 10% of stones.

In the middle you'll get 30% in moon grade. These also have a fine grain but not as uniform. Some manufacturer's like Mr. Kuroki don't use moon grading anymore which I find a bit of a shame.

Towards to base of the shell you'll get about 60% of your stones, these are the Standard or Practical grade (the wording is interchangeable). There are two types of practical grade that I've seen. One (the kind Mr. Kuroki makes) that is nicer and has a strait grain across and the other where the grain loops in an arc around the shell.

Here are some snow grade Mexican Clam stones...sadly these are old pictures. I'm in China at the moment and can't use my personal collection as an example (and why I'm not selling at the moment on Ebay). Sorry these pictures are rather big...but it will help show the detail







Hyuga (Japanese) clamshell (Called Suwabute) is not graded the same way as Mexican clamshell because the grain is exceptionally fine and uniform grain throughout. So much so that it puts to shame even Mexican snow grade. Instead Hyuga stones are graded mostly on their color. The uncut shell is quite beautiful and rather colorful. "Standard" grade is called "Flower" grade and will have a warm, orange glow throughout. Moon grade will have less color, but nonetheless still noticeable. Snow grade will be milky white with just a tinge of orange coloring giving the stones a slight warmth.

The grain in Hyuga stones will often have a slight angle to it, and in sizes 28+ you'll often see a curvature/arc in the grain towards the center (more common the larger the stones are...I almost never see it below size 25).

So you can identify Hyuga stones on three points. 1. Grain, 2. Color, 3. Angle/curvature of grain.

You'll never find Hyuga stones larger than size 40...in fact you can count on one hand the number of sets that have ever existed in that size. The shells grow much slower (and not as large) than Mexican shells which is why they are rarer and the price rises exponentially with each size increment. I once held a set of size 40 stones...each one was worth almost two times more than it's weight in gold (at current market value)

I have some hyuga pictures I'll show you, but I can only load three per post, so I'll put them in just a moment.

Here are the Hyuga (Suwabute) stones. I couldn't get my best picture to upload, so the first photo is a little more orange than normal snow grade, but still good.

One more grouping of Hyuga (Suwabute) pictures