Shippiki Cut-Off Tools Naomi Tsukamoto

Appears in the Jan/Feb 2015 issue of Pottery Making Illustrated.

Many Japanese pottery tools are highly specialized and sometimes look a bit different from the ones in the US. When you’re throwing off the hump, it’s not easy to cut the bottom of the finished piece even and keep the shape of the pot from distorting when using a cutting wire. Shippiki is a Japanese cutting tool for such occasions.

The word shippiki originates in the Seto area of central Japan, a region known for blue-and-white porcelain called Seto ware. The word means pulling the bottom or the hip.

Make Your Own Shippiki

Japanese potters usually make their own shippiki with leveling line (similar to a carpenter’s chalk line). The length depends on the sizes of the thrown forms (a shippiki is usually used for small to medium-sized pieces and not for large forms), but they are usually less than 10 inches long. Make a loop on one side so that it’s easier to pull the string to one side once the piece is cut. Sometimes, a short wooden dowel or a cork is tied on one end instead of creating a loop (figure 1). A benefit of using a cork is that it will float if the shippiki ends up in your water bucket, making it easier to find when you need it.

Using a Shippiki—For Beginners

First, make a light indentation in your thrown form using your finger to mark the bottom of your finished piece. After creating this guideline or groove in the foot,  you’re ready to use the shippiki.

Note: The images show a potter’s wheel spinning in a clockwise direction as that is typical in Japan. In the US, many people throw with the wheel spinning counterclockwise, so the written directions reflect the steps needed for a counterclockwise-spinning wheel.

With the wheel stopped or spinning very slowly, manually wrap the string around the bottom of the form one-and-a-half times, keeping it in the groove. Stop the wheel. Hold the loop in your left hand, and keep the thumb and index finger of your right hand against the side of the foot, over the groove to guide the shippiki and keep it in place (figure 2).

Start spinning the wheel again at a slow to medium speed and pull the shippiki horizontally away from the center of the wheelhead with the hand holding the loop. The part of the shippiki that is in the groove will cut through the foot as you pull it with your left hand and as the wheel rotate.

Advanced Technique

With the wheel rotating slowly, stretch the string tight using both hands. Hold it in front of the piece, with the looped side in your left hand (figure 3). Slowly insert the string into the groove parallel to the wheel head. The string gets caught on the form and guided into the groove as the wheel rotates. Release the string from your right hand (figure 4). It will start rotating with the wheel. Once the string rotates one-and-a-half times around, slowly pull the string horizontally to your left with your left hand (figure 5), keeping the string parallel to the wheel head, then stop the wheel. Now the piece is cut, and you can take it off the hump.

Thank you to my Japanese colleagues at Takara Clay Studio, a community-based pottery school located in Kamakura, Japan, for helping me demonstrate the Japanese tools. You can see the video demonstration of the using a shippiki on Takara Clay Studio’s website at takaranokama.com/raku.html.

Naomi Tsukamoto runs a ceramic and flower studio with her florist husband in Japan.