original picture by Iiyama Takashi
The distinct diamond pattern on the handle of a samurai sword is probably one of the most characteristic elements of a Japanese sword.
The underlying rayskin is shown by folding and guiding tsuka-ito ('handle thread') over the wooden handle core. By using different techniques you can influence the the exact shape of these hishi (~diamond shape) to adapt the overall outlook.
While rayskin showing wrapping styles (such as moro-tsumami-maki and moro-hineri-maki) are indeed the most common, many obscure wrapping techniques can be found in Japanese history. Some of which do not show the underlying rayskin.
It's important to know that different periods and different regions in ancient Japan had their own specific materials and wrapping techniques. This picture is a great example of an exotic wrapping technique.
革雁木巻 or Kawa-gangi-maki may at first seem like a pragmatic or maybe even simple way of wrapping. However when trying to retrieve the exact methods that were used, the spirit behind the art of tsukamaki will reveal itself :) I will be restoring a handle in 'gangi-maki' soon but here's how it's supposed to look ;)