Ray skin becomes very hard in dry, and becomes soft in wet. So it is useful to make a hard handle.
It has uneven thickness in parts. Around the large nodule is thickest. Craftsman wraps a wet ray to check a good fit with the handle wood, then shaves the handle wood. He makes the temporary wrapping again and again until the final work to use the glue.
(=> Actual examples of producing KOSHIRAE)
 
-Several styles of Wrapping-
(The blue part is ray skin. It is a view from the fuchi and the reverse side of handle wood. The fuchi and kashira are removed in the pictures.)
(In the pictures, the ray skin doesn't run under the fuchi to make drawing simple. But, in actual work, ray skin can wrap the whole handle wood also under the metal fittings.)

Tanzaku (Channelled)
This style is used only for cheap swords. It is small meaning to use ray skin. Sometimes there is a line on the reverse side to trick it for Marugise. Usually it is made of the second pieces of ray skin.

 
Marugise (Round wrapped)
It is common on good quality swords. Usually the joint is at the centre of reverse side. Sometimes it can be placed near the back or near the cutting edge.



An old handle wood with ray skin wrapped by Marugise style.


 
Maedare-gise (Round and Half)
This style is the most tough. But it was not common in old days. Because, it is not easy to make a good work, and expend much ray skin. We can find this style of handle only on the swords in feudal lord collections, or some Samurai's who prepare his sword carefully.


An actual example of handle wood for maedare wrapping. The kashira is a buffalo horn.


The view from the cutting edge side.

The view from the back side.

The ray skin is wrapped up with glue.




 
In Koto period, it is common to harden the ray skin with urushi lacquer, because ray skin is weak against the rain. White ray skin is used on parade swords or noble's swords.
In Shinto period, white ray skin is not rare.
The Edo government took the policy of national isolation, and they had been kept peace over 200 years.
I wonder if ray skin became more expensive, and people forgot to prepare their sword for battle field.
 
 
We have received a question from a customer.
Do the craftsman prepare the mune and ha area on the ray skin with paper panels?
Or does he do tsukamaki directly on the nodules?
(tsukamaki = the work wrapping with cord)
 
Usually the mune and ha is prepared with paper or wood panels to make a smooth surface for tsukamaki. The level between the fuch/kashira and the wrapped cord surface must be even. Some craftsman says, the panels are necessary to make a proper surface on ha/mune. Such a method is common in Edo period.
 
A foundation work of tsukamaki.
The ha and the mune are wood panels. The start and the end are black papers. The ray skin is maedare-gise.



 
An example of broken handle from Edo period. The ha/mune surfaces are revised with panels.


The ray skin wrapping style is Marugise (round), but the area near the fuchi is patch work with the second pieces.
 
Another example of broken handle. There are paper panels on the ha/mune and the area start and end.


 
Before 16th century, in Koto period, the method seems a little different.
I studied some old koshirae's from the Koto period. The tsukamaki surface on ha and mune has small risings of nodules. In other words, we can see the nodules over the wrapping. That means the handle under the wrapping is not smooth, it still has nodules. So we can see that the handle has no panels on its ha/mune.
It is not easy to make a even surface without panels. The work of ray skin wrapping has to be done more exactly than the case using panels.
The directly wrapped handle is better to swing the sword. The wrapped cord is hard to move, because the nodules bite into the cord. Therefore the direction of the ray is important.