Tools of Japanese carpentry

Standard set of tools

The defining features of Japanese carpentry tools are their exceptional sharpness and wide variety. A 1943 survey of tools owned by carpenters living in Tokyo found that 179 carpentry tools were necessary to construct a full-scale building. 87 of these tools are exhibited here.

A. Sumi-kake dōgu (Marking tools)

The sumi-tsubo (carpenter's line) originated in China and is a tool unique to Asia. Literally ‘ink pot’, the sumi-tsubo is used for drawing straight lines and marking. Notably it is one of the only tools that is intricately carved.

B. Suji-kebiki (Marking gauges)

A marking gauge is a tool used to draw lines parallel to a surface used as a reference.

C. Nokogiri (Saw)

A significant feature of Japanese saws is that they cut on the pull stroke. This allows a thinner blade, enabling more precise work. Depending on the direction of the cut relative to the wood grain, Japanese saws are classified into two types: ripsaws that cut along the wood grain and crosscut saws that cut across it. In addition, there are double-edged saws with both ripping and cross-cutting blades.

D. Nomi (Chisels)

Chisels are broadly categorized into striking chisels and paring chisels depending on their purpose. Striking chisels are used with a hammer or mallet to create mortise holes for joints or to remove excess material. To withstand striking, they have an iron ring called a katsura on the head of the handle. Paring chisels are used to finish areas carved with a striking chisel or to smooth small areas that cannot be planed. Chisels come in various blade widths suited for different tasks.

E. Kiri (Gimlet)

A gimlet, or kiri, is a tool used to create round holes by rotating its pointed edge. The shape of the cutting edge varies depending on the purpose and material. Hand gimlets were traditionally used to make nail holes, but with the introduction of European and American-style bolt-based architecture in the Meiji period (1868–1912), screw-shaped gimlets became common.

F. Kanna (Plane)

Japan is the only country where planes (kanna) are pulled rather than pushed. These tools are used to smooth the surface of boards and square-edged timber. There are two blade types: a single blade and a laminated double blade. Originally, all planes had a single blade, but in the late Meiji period (1868–1912), the laminated double blade, or awase-kanna, was introduced. This new plane reduced surface irregularities caused by shaving against the wood grain and quickly became the norm.

G. Gennō (Hammer)

The gennō, a type of Japanese hammer, is mainly used for striking chisels or driving nails. There are several types differing in the shape of the iron head: the ryōguchi-gennō has two flat striking faces, called koguchi, of equal surface area, whereas the funate-gennō and the kataguchi-gennō have one end pointed and the other flat.

H. Maintenance tools

Toishi (Whetstone or sharpening stone)

Whetstones are used to sharpen the blades of chisels and planes by drawing the blade across the stone at a precise angle. Most Japanese whetstones are made of natural stone shaped into a rectangular form, but in recent years, synthetic whetstones have also become common. In Japan, whetstones are classified into three primary categories according to the grit size of their abrasive particles: coarse (ara-to), medium (naka-to), and fine finishing stones (shiage-to).

Asari-tsuchi (Asari hammer)

Metate-yasuri (Saw file)

Dainaoshi ganna (Sole tuning plane)

I.  Other tools

Flat-blade screwdriver

Kuginuki (Enmma) (Pincers)

Kitsuchi (Mallet)

Jōgi (Measuring tool)

Ono (Axe)

Axes with narrow blades are called ono, while broadaxes with wider blades and a tapered edge on one side are referred to as masakari.

Ono are broadly divided into two major categories, cutting axes (kiri-ono) and splitting axes (wari-ono), both used for forestry work. Small splitting axes with a short handle are called kowari-ono and are used for splitting timber into small pieces. 

Masakari are mainly used to smooth and finish timber. There are two types of masakari. One has a longer handle and is mainly used for timber processing. The other, called the carpenter's broadaxe (daiku-masakari), has a shorter handle and is used for rough carpentry or making wedges from wood scraps.

1. Kiri-ono (Yoki) (Cutting axe)

2-4. Masakari (Rough grinding axe)

5. Daiku-masakari (Carpenter's hewing axe)

Maebiki-oga (Wide blade saw)

In Japan, up until the mid-Muromachi period (1333–1573) there were no vertical saws. Instead, timber was processed using splitting techniques with chisels. With the introduction from the Asian continent of the oga (a large vertical ripsaw operated by two people), timber processing improved significantly, greatly advancing architectural production. The oga was quickly replaced by the maebiki-oga (a one-person ripsaw with a wide blade unique to Japan) and the gagari (a saw for small-scale splitting). These remained the main tools for timber processing until the mid-Meiji period (1868–1912).