Pewter is an excellent rust-resistant material with substantial weight. Pewter is soft enough to be easily bent by hand. To add strength to such soft material against easy bending, a hammer is used to beat the pewter to tighten the molecule structure, producing minute undulations as a result. It also changes the way the surface looks and improves the way it feels to touch. This was how the technique to create three-dimensional shapes from pewter was developed. The shining surface beams with a sense of cleanliness. This is called hikimono.