Generically, inlay (intarsia) is a technique whereby a geometric or other pattern is incised into the metal (or wood, e.g., for hilt or scabbard) by file, chisel or saw. Into these grooves, wire or other material is laid. It is hammered into place and the surface typically filed smoothed to match the surrounding material. Inlay can occur at various stages of assembly of the knife or sword, depending on the dictates of the design and materials used.
See also Koftgiri, of which one type, Te-hen-shah or "Deep inlay", uses the technique described above.
There are three types of inlay used in Japan and not seen elsewhere. "Uttori zogan" is a technique for inlaying pieces of a design that are quite large and thick. The piece is set into a recess and then edges set with a punch. Flanges and grooves may also be used. The projecting part of the inlaid piece is typically carved and sometimes itself inlaid with other metals. A technique related to fire-gilding is used in Japan to make very small dots to represent mist or very fine characters that are quite small. Hollow holes or lines are cut into the base metal and into these a gold amalgam is poured. After heating, the solid gold is left in the holes rather than on the surface as in fire-gilding.
Wood Inlay
Wooden inlay is a technique where different colored woods are used to create a predetermined image for aesthetic appeal. It is believed to be one of the most decorative forms of forest wood product. The two major types of wooden inlay are marquetry and parquetry. The techniques for these wooden designs are different and have also changed over time. Overall there are many reasons why wooden inlay is and should be used.
- Marquetry
Marquetry has a long history and is slowly becoming an extremely popular hobby. Marquetry is the art of painting with wood. Also called intarsia it encompasses making pictures and geometric designs with thin slices of colored wood. It is a popular technique for decorating the smooth surfaces of pieces of furniture, as well as a versatile means of creative expression. Both inlay and overlay (veneer) methods are used.
- Parquetry
Parquetry on the other hand does not have as long a history but is also becoming more popular as time goes on. Designs are entirely geometric and angular (such as herringbone) mosaics. It is more common in larger projects as the pieces tend to be larger.