Info and a collector's opinion on Kuroki Goishi Ten's stones

A set of Yuki (Snow) Grade stones with Keyaki bowls.

Image from Kuroki Goishi Ten's website.

During my three-week break from playing online Go, I was contacted by a collector who was very kind to fill me in on the details regarding Kuroki Goishi Ten's (hereafter referred to as KGT) slate and shell stones. This gentleman had been collecting boards and stones for several years but discovered Mr. Kuroki's wares in the summer of 2003. He has since become a loyal customer and acquired several boards and stones, including some from Mr. Kuroki's specialty offerings. He has also maintained a very active correspondence with Mr. Kuroki.

I had two rather lengthy phone conversations with this collector and I wanted to share some of what I had learned from him in preparation for my purchase decisions.

Stone Sourcing

Hyuga

KGT sources clamshells to make its white stones from Mexico and locally in Hyuga (Miyazaki Prefecture), Japan. KGT describes Hyuga clamshells as having "finer patterns and a more elegant milk-white color than their Mexican cousins" and thus they are priced considerably higher.

Stone Grading
You will currently find four grades of stones on KGT's website and the list below shows how they rank with regards to quality and price (best to least) when taking into account the sourcing of the clamshells.

1. Hyuga Clam Snow Grade (Yuki)
2. Hyuga Clam Moon Grade
3. Hyuga Clam Flower Grade (Hana)
4. Snow Grade (Mexican Clam, Hyuga-crafted)
5. Moon Grade (Mexican Clam, Hyuga-crafted)
6. Flower Grade (Mexican Clam, Hyuga-crafted)
7. Standard Grade (Mexican Clam, Hyuga-crafted)

My understanding is that the Moon Grade and Standard grade stones are being phased-out so KGT will eventually carry only Snow and Flower grades. The image below (click to enlarge) will show you the difference between the tightness and straightness of the patterns between these two grades.

Snow versus Flower (sometimes translated as Bloom) grade.
Image from Kuroki Goishi Ten's website.

The Standard grade stones tend to be less glossy than the others suggesting that it goes through a short polishing process. With a long polishing process, there is a greater chance of the stone chipping.

Sizes
While personal preferences vary, most Go players that I have know favor stones that have heft and that are about 10mm thick. KGT's size 36 stones measure 10.1mm in thickness. The photos below will give you an idea of the relative thicknesses.

Sizes 22 to 33
Image from Kuroki Goishi Ten's website.

Sizes 34 to 40
Image from Kuroki Goishi Ten's website.

Cost
I've listed some of the prices to give you an idea of the relative value of these grades and sizes. I wanted to do a standardized comparison but not all grades were available in the same size. I don't think you'll miss the point, though.

• Hyuga Clam, Snow Grade, Size 40, 40,000,000 Yen (approx. $370,000)
• Hyuga Clam, Snow Grade, Size 38, 15,000,000 Yen (approx. $139,000)
• Hyuga Clam, Flower Grade, Size 31, 100,000 Yen (approx. $925)
• Mexican Clam, Snow Grade, Size 31, 30,000 Yen (approx. $278)
• Mexican Clam, Flower Grade, Size 31, 25,000 Yen (approx. $231)

Keep in mind that the clientele for the high-end stones tend to be wealthy Japanese industrialists with the means to pay.

Comparative Quality
The gentleman I spoke to had acquired slate and shell stones from all the major vendors to the US along with three others that had gone out of business many years ago. As such, he was in a unique position to assess KGT's stones. It was his humble but strongly-asserted opinion as a collector that KGT's Standard grade conformed to everyone else's Snow grade.

To be fair, it's unclear as to how KGT's stones compare to other Hyuga-based vendors but KGT is currently the only one that has made their wares accessible to English-speaking clients via the internet.

Considerations When Buying
I was told that Mr. Kuroki has his best prices listed on his website's English best-buy page. The set pictured below costs about $333 and offers (1) Size 32, Mexican-clam, Moon Grade stones, (2) extra-large bowls made of New Sakura, and (3) a 5cm thick New Kaya table Go board.

Image from Kuroki Goishi Ten's website.

You can, and probably should, take the time to write to him via email and inquire about other packages that he might not have listed on his website. You should also inquire as to what the shipping costs would be via air and surface mail. Estimated costs to California would run 8,400 Yen ($78) for surface freight and 17,500 Yen ($162) for air freight.

I was told that he is a wonderfully attentive and polite man to do business with. Replies may take at least 2-3 days as he needs to have his English emails translated.

Most credit cards will charge a transaction fee of about 3% for foreign currency purchases. 2% goes to Visa/MasterCard and 1% goes to your card issuer.