【Introduction to Traditional Crafts】 ～Nagasaki Tortoiseshell (Nagasaki Prefecture)～
2022.12.27 
About Japan's Traditional Crafts
【name】
Nagasaki Tortoiseshell
【Production area of Nagasaki Tortoiseshell】
Nagasaki City, Isahaya City, Saikai City, Nagayo Town, etc. in Nagasaki Prefecture
【What is Nagasaki Tortoiseshell?】
Tortoiseshell work produced in Nagasaki City, Isahaya City, Saikai City, Nagayo Town, etc. in Nagasaki Prefecture.
The material is the shell of the hawksbill sea turtle, a member of the sea turtle family.
It lives in relatively warm waters, and its shell has a beautiful mosaic pattern, so it has long been used as a raw material for tortoiseshell work.
Nagasaki was the only city allowed to trade with other countries during Japan’s isolation.
It is believed that tortoiseshell work developed in Nagasaki, partly because it was an environment in which it was easy to obtain materials.
However, since 1977, the CITES prohibits international trade in hawksbill turtles for commercial purposes.
It became impossible to import raw materials, and the rarity value of Nagasaki tortoiseshell has increased.
In 1979, it was designated as a traditional craft.
【Features of Nagasaki Tortoiseshell】
The characteristics are “beautiful patterns with unique colors”, “abundance of types” and “non-slip even when worn”.
・Beautiful pattern with unique color
This is exactly the result of the skills and years of experience of craftsmen.
When making products with curves, the hawksbill turtle shell is boiled in boiling water to soften before use.
The craftsmen work by adjusting the processing speed depending on how the heat is transferred and how it cools down.
By carefully polishing it, it becomes shiny, and it can be said that it is unique to the delicate and skilled technique of craftsmen.
・Rich variety
There are so many types of Nagasaki tortoiseshell that it seems that there is nothing that cannot be made.
In addition to small daily necessities such as hair ornaments, combs and accessories, large products such as telephones and ship figurines are also made.
・It is hard to slip even if you wear it
Nagasaki tortoiseshell, which is directly worn as a ring, changes little by little according to the body temperature and fits into a shape that suits the owner.
In addition, since the direction of the fibers is constant, it is difficult to slip.
【History of Nagasaki Tortoiseshell】
Tortoiseshell work itself has a long history, and it is said that it was introduced from mainland China between the Asuka and Nara periods.
Some of the works said to be from that period are preserved in the Shosoin at Todaiji Temple.
Japan was closed from 1641 to 1853, but hawksbill turtles began to be imported during this period.
This is how Nagasaki tortoiseshell came to be made.
At that time, tortoiseshell was an auspicious object to celebrate longevity.
In addition, combs and hairpins were treasured by wealthy people, including feudal lords throughout Japan.
On the other hand, it was originally expensive and difficult for the common people to afford, but it was extremely valuable to the common people, partly because laws and ordinances that prohibited luxury were often issued.
When the national isolation policy was abolished in the Edo period, people from various countries came and went to Nagasaki.
Nagasaki tortoiseshell began to be used by foreigners as well, and craftsmen continued to study so that they could continue to use it even after returning to their home countries.
In this way, Nagasaki tortoiseshell is highly evaluated not only in Japan but also overseas.
Even now, it is widely known as a specialty of Nagasaki.
【Production process of Nagasaki Tortoiseshell】
①Design
First create a design proposal.
Since the material is limited to natural materials (hawksbill turtle), there are restrictions on the overall size and thickness.
②Selection of fabric
referring source：Nagasaki Tortoiseshell Association Federation
Depending on the work, select the fabric from the hawksbill turtle’s “back (the part on the back side of the shell)”, “fence (the part on the outside of the back)”, and “plastron (the shell on the abdomen)”.
③Cutting
Cut the fabric according to the design with a scroll saw.
The parts used are all different in color, pattern, etc.
It is important to cut so that the original beauty of the material is not lost.
④Kisagi
It is a work to cleanly remove mixed things and dirt using tools such as files.
This is done until the surface becomes smooth.
⑤Hibashi
Nagasaki tortoiseshell is made by layering thin materials.
When joining them in the later process, they must be temporarily attached to prevent them from slipping.
It is done using hot tongs.
⑥Press
The shells are sandwiched between heated iron plates and pressed.
By compressing, create a tortoiseshell fabric with a uniform thickness.
No adhesives are used at all, and only water and heat are used to bond, so it is called “the art of water and heat.”
⑦Push iron
When it is necessary to stick tortoiseshell on wood, craftsmen use egg white instead of glue.
After using egg whites between the shell and the wood, the craftsmen glue them together with a hot trowel.
⑧Sculpture
Engrave according to the design proposal made first.
The more delicate the design is, the more skillful technique is required.
⑨Polished
In order to bring out the luster peculiar to tortoiseshell, it is polished.
⑩Assembly
Attach metal fittings to brooches and earrings, and assemble each part to complete.