NEWS[Clamshell Go Stones] Information Regarding New Products & Prices

Kurokigoishiten was established in 1917 in Hyuga City, Miyazaki Pref., as a manufacturer of clamshell Go stones. We are going to commemorate our centennial anniversary in 2017. We would like to express our heartfelt gratitude for the kindest and continuous support of all our customers around the world.

We are happy to inform our customers that starting from January 1st, 2016, we will release NEW Clamshell Go stones made of Mexican clamshells.

Introducing a “New Numbering System” for our stones! (※Application for “utility model patent” pending)

Each clamshell stone produced in our workshop carries specific numbers on its surface. This numbering system will help us track our products and clarify our liability. We will continue to make every effort to further improve the quality of our products and our quality assurance system.
*The numbers become visible when the stones are exposed to black (ultraviolet) light.numbering-1 This new numbering system will help us further improve our quality control and assurance system. Up until now, manufacturers had no unified sorting standards, which makes it hard for customers to distinguish genuine brand stones from inferior/second-hand ones. Many customers find it extremely hard to know the true value of clamshell stones. We believe that our newly-introduced numbering system will help customers around the world understand our strong commitment to our products and liability.


Starting from January 1st, 2016, we are happy to introduce the following three grades.

Carefully selected “SNOW GRADE”

雪印 This category includes the most carefully selected clamshell stones that possess the highest grade in terms of shape, color, and presence of scratches. These three factors are checked against our venerable Master Stones for comparison. All stones have beautiful clear stripes on their milky surface, which are specific to natural clamshell. The product is delivered in our original paulownia wooden box.

Carefully selected “BLOSSOM GRADE”

華印 This is the second highest grade clamshell stones in terms of shape, color, and presence of scratches that pass the standard of our venerable Master Stones. The distance between each stripe varies from close to wide. The product is delivered in our original paulownia wooden box.


“BLUE LABEL” stones are the perfect gift for beginners. They are also good to use at Go tournaments and Go parlors. We hope that more entry-level and recreational players will have a chance to play with these real clamshell stones. Their quality is nearly equal to that of our two highest grades. The product is delivered in a wooden box. bluelabel750

We decided to reduce our number of Go stone sizes.

Today, stricter regulations in protected areas in Mexico make it difficult for us to dig more natural clamshells from those beaches. In addition, the quality and the number of natural clamshells have been gradually decreasing. Because of this, we decided to reduce our number of “Stone Sizes” in order to streamline all our production and sales processes.

Hyuga Clamshell Go Stones (white): Size is standardized based on thickness.

*All black stones are 0.3 mm thicker than white stones.

Size 28 Actual thickness: Min. 7.5 mm
Size 30 Actual thickness: Min. 8.0 mm
Size 32 Actual thickness: Min. 8.8 mm
Size 34 Actual thickness: Min. 9.5 mm
Size 36 Actual thickness: Min. 10.1 mm
Size 38 Actual thickness: Min. 10.7 mm
Size 40 Actual thickness: Min. 11.3 mm


As previously explained, it is becoming harder to collect natural clamshells. Please be advised that we have decided to set new prices for clamshell Go stones as shown below, in accordance with our special traditional skills and expertise required to make clamshell Go stones. We are going to improve our after-sale services so that all our customers will be able to use our products for a long time.
*All prices below refer to a “set price”, that includes 180 clamshell stones (white) and 181 Nachiguro slate stones (black). (Tax not incl.)

Carefully-selected “SNOW GRADE” (thickness in mm)

Size 28(7.5 mm) 60,000JPY
Size 30(8.0 mm) 90,000JPY
Size 32(8.8mm) 140,000JPY
Size 34(9.5mm) 250,000JPY
Size 36(10.1mm) 330,000JPY
Size 38(10.7mm) 420,000JPY
Size 40(11.3mm) 720,000JPY

Carefully-selected “BLOSSOM GRADE” (thickness in mm)

Size 28(7.5mm) 35,000JPY
Size 30(8.0mm) 39,000JPY
Size 32(8.8mm) 50,000JPY
Size 34(9.5mm) 63,000JPY
Size 36(10.1mm) 79,000JPY
Size 38(10.7mm) 104,000JPY
Size 40(11.3mm) 155,000JPY

“BLUE LABEL” (thickness in mm)

Size 28(7.5mm) 17,000JPY
Size 30(8.0mm) 20,000JPY
Size 32(8.8mm) 25,000JPY
Size 34(9.5mm) 32,000JPY
Size 36(10.1mm) 40,000JPY
Size 38(10.7mm) 52,000JPY
Size 40(11.3mm) 77,000JPY

We will make every effort to offer all our customers products of the highest quality. We look forward to your kind and continuous support to Kirokigoishiten. Thank you very much.