Carpentry Tools > Hammer



The genno is mainly used for striking a chisel or driving a nail. There are several types that differ in the shape of the iron head: the ryoguchi-genno has two striking surfaces (koguchi) of equal surface area whereas the funate-genno and the kataguchi-genno have one side of the head narrowed down to a wedge shape.

The striking surfaces of the ryoguchi-genno have different shapes; one is flat and the other bulges out slightly in the centre. The flat side is used for striking chisels and driving nails, while the convex side called the kigoroshi-men (literally the "wood killing surface") is used to flatten timber surfaces. It is also used for lightly tapping the final strike when driving a nail to avoid leaving marks on the timber.

The size of a genno is measured in terms of weight and the traditional Japanese unit monme is still being used today. Gennos used for rough work usually weigh 100 monme (375g). The handle is generally made of oak.


  Column : The derivation of the name genno
A passage from an Edo era book "Yoshu-fushi" (1986) suggests the origins of the name genno: "Once upon a time, in a place called Nasuno in the ancient country of Musashi, there was a monstrous stone that would force birds to fall from the sky and animals to die when touched. A monk called Genno decided to put an end to this, and uttering the mantra, he stroke down onto the stone with a large sledge hammer breaking it into pieces. Since then the sledge hammer came to be called genno".

From left to right: ryoguchi-genno, funate-genno, kataguchi-genno

 
The Kanazuchi is used principally for driving nails, and unlike the genno has one flat striking surface and one wedge-shaped striking surface used for example to drive nails into narrow corners. The most representative types are the sakigiri-kanazuchi, the shitahara-kanazuchi and the yonbun-no-ichi-kanazuchi (quarter hammer).

From left to right:sakigiri-kanazuchi,shitahara-kanazuchi,shitahara-kanazuchi

 
The ki-zuchi is used principally for extracting or inserting the blade of a plane. The edge of the plane is tapped when extracting the blade, and the blade itself is tapped when inserting it into the plane.

From left to right:ki-zuchi, kariwaku-zuchi, kawaraya-zuchi


The contents of this page are excerpts from Takenaka Carpentry Tools Museum Collection Catalogue no. 6 -tsuchi, ono, masakari and other tools-
The name of the tools are those used at the museum which are mainly based on those used in western Japan. The names can vary according to the place and the researcher.


 
ink pot carpenter's square marking gauge saw chisel
plane gimlet hammer ax and broadax

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