This fountain pen is made with "Kirigane," a technique using real gold leaf.

Whta is Kirikane?
Kirikane was introduced to Japan in the 6th century through Buddhism.
It is a traditional Japanese technique using gold, silver or platinum leaf, which is then cut into thin strips and applied as patterns using a brush and special glue(Nikawa)
It was developed as a technique for Buddhist art decoration (statues and paintings), and it is now used in Japan, mainly in Kyoto to decorate special art and craft materials.

Enami (sea wave)
Like hemp leaf, this pattern has been used to decorate Buddhist statues since ancient times.
It is a pattern that depicts the blessings of the vast oceans, and the waves spreading out endlessly are a good omen for future happiness and a peaceful life.