Japanese carpentry relies on a straight, thin centreline as the basis of clear marking out - and the tight-fitting joinery that follows.

This line is laid down with a sumitsubo, or ink line. Although many hundreds of years old, the sumitsubo is still around in it's traditional form - as well as more modern models with extra bells and whistles.

Shinwa's ink lines have been refined continuously for may years to add convenience and ease of use to a highly reliable tool.