Marking Tools (Sumitsuke-Dogu)

Japanese traditional marking tools come in all shapes and sizes. Many might seem familiar to their Western counterparts at first glance. Here’s a brief overview of the key marking tools you’ll find in a Japanese carpenter’s toolbox.

Sumitsubo | Ink Pot

The sumitsubo is used to mark straight lines in a similar manner to a Western chalk line. Silk string line is wound on a wheel and passes through a bowl (tsubo). As the line is drawn through it picks up ink. The line can be drawn out and snapped onto a surface leaving a fine line. Sumitsubo have a significance for carpenters that extends beyond their day to day use. Some are covered in ornate carvings, like the featured image with turtles, and are used in ceremonies or presented as gifts.

The reverence this tool is shown could be due to the importance that Japanese carpenters place in accurate marking at the beginning of construction. In Japanese Woodworking Tools: Their Tradition, Spirit and Use, Toshio Odate recounts that it was customary that the master carpenter would begin construction by using the sumitsubo to snap a line on one of the major timbers. A duty reserved for him and his only duty on that day.

Sumisashi | Bamboo Pen

The sumitsubo is also used to dip a bamboo pen called a sumisashi. The point of the pen (Kaeshi) is prepared so that it can be used to make precise marking out of joinery.

Sashigane | Square

The sashigane is a metal right-angled ruler. It is similar in appearance to a Western framing square. Although modern examples are often marked with metric (cm) and even imperial (inches) intervals, a traditional sashigane is marked using the Japanese measurement system. The sashigane is marked on both the front and back. The front side is divided into intervals of one sun each of which is divided into 10 bu. One sun is roughly equivalent to an inch. The back side (ura-me) is marked using the same system but multiplied by the square root of 2. When measuring the diagonal of a square, the ura-me computes the length of the sides. By using the ura-me side to measure the diameter of the circle, the reading will show the length of the sides (in sun) of the largest square that can fit in that circle. A carpenter or sawyer can use this to determine the largest square column that can be cut from a cylindrical log. The ura-me side on some sashigane are marked by dividing the front-side values by pi. This can be used to determine the circumference of a circle. 

Unlike a Western framing square, the sashigane is flexible and the blades are thin so that it can be held against a surface and pressed flat. The blade has a profile that lifts the edge used for marking slightly off the surface of the wood. This allows the tip of the sumisashi to ride along the edge without ink being drawn under the blade and on to the surface being marked. The sashigane can be positioned if needed so that the edge is in contact with the surface for accurate measuring.

Makigane | Small Square

The makigane is a small square that is often used to check the squareness of the sides of narrow stock commonly used for rails and stiles. It is constructed from a thick stock and a narrow blade; the same way a western try square is made.

Daiku No Makigane | Carpenter’s Square

The daiku no makigane is similar to the sashigane, but smaller and more rigid. The tongue (the shorter arm) has a tapered profile that allows it to lay flat on the surface while the body registers against the adjacent surface. It is better suited for the task of marking square lines at 90 degrees to the other surface than the sashigane.

Ogane | Large Square

The ogane is a large square which would typically be made on site at the construction of a building. It is used to check the squareness of the outlines of a building.

Suji-keshiki | Line-Marking Gauge

The suji-keshiki is a general-purpose line marking gauge or keshiki. It is a close relative of Western marking gauges and can come in lengths suitable for small pieces and also longer lengths for marking panels. In a traditional suji-keshiki, a blade made from laminated steel is used although carpenters will often use whatever is available when making their own. The bevel of the blade can be customised for the wood types being marked. The suji-keshi can be made with two beams for the purpose of marking out the sides of a mortise.

Ana-keshiki | Mortise Gauge

The ana-keshiki is used to mark the sides of mortices. The ana-keshiki uses pins for marking that are inserted at a fixed distance and then shaped to match the width of a mortices chisel exactly. An ana-keshiki can be setup to match the width of several morticing chisels by using other sides and ends of the beam. The stock of the ana-keshiki is 2” square and is fitted to the beam with a friction fit that does not require a wedge.
The ana-keshiki is best suited where mortice and tenon joinery is applied consistently as is often the case in cabinet making and screen door making.

Kama-keshiki | Sickle Gauge

The kama-keshiki can be used to mark mortices or single lines. Instead of a wooden beam, the beam is formed by blades that ride in a groove. The two blades move independently of each other to scribe varying widths of mortices. One blade can be retracted into a recess cut into the stock so the gauge can be used to mark a single line.

Wari-keshiki | Splitting Gauge

The wari-keshiki is used to split thin stock. It is similar to the suji-keshiki but has a larger stock and blade to allow force to be applied to the blade to cut deeper into the wood. The gauge is run along the piece of wood several times and from both sides if necessary, until the piece splits cleanly along the line.

Shirabiki | Marking Knife

The marking knife is similar to a Japanese woodworking knife, but the bevelled edge is at a steeper angle to the side of the knife. They are often made from laminated steel and need to be set up in a similar way to a chisel. The knife is intended to mark across the grain where greater accuracy is required than can be given with an ink mark. It can also be used to help guide a chisel or a saw by providing an initial groove for the tool to rest in when starting the cut.

Kigata-Jogi | Block Gauge

Kigata-Jogi are used for marking lines or guiding tools relative to a reference face. They typically provide a reference at 90 or 45 degrees to the reference edge. They are traditionally made by the woodworker out of wood but are now commonly available made out of steel.

Shakaku-Jogi | Bevel Gauge

The Shakaku-Jogi is an adjustable gauge that can be used to to set an angle and transfer that angle to another surface. It is nearly identical to a western bevel gauge but has slightly different proportions.

Where Can I Buy Japanese Marking Tools?

Be sure to check out our Tool Suppliers section for a host of independent retailers based in Japan who sell their wares online or through eBay.

Huge thanks to Eric Jutrzenka for writing the content for this page. If you’re interested in becoming a Contributor to the JWA website, click here.