The fundamentals of tsuba design

The fundamentals of tsuba design

Postby Ford » Tue May 30, 2017 5:56 pm

In an attempt to clarify the details of fuctional tsuba design I'm going to use this thread to build up a running tutorial on those aspects I feel are often misunderstood or not recognised.

One of the first, and perhaps most important, points we need to focus on is the positioning of the nakago-ana, the opening in the centre through which the tang (nakago) of a sword must pass. Oops, sorry, I find myself unavoidably adopting my 'authorial voice' now after spending so much time lately rewriting the final draft of my book. :redface:

Hopefully the following images of templates I regularly use will make things easy to see.
And please note that although the horizontal scribed lines you can see appear not to be running parallel that is just an illusion due to the camera not being exactly in the same plane, ok? :biggrin:

Click on the images to see them enlarged :cheerleader:

This image shows a habaki on a modern (American made) blade. Notice how the nakago is naturally narrower than the blade's full width and how, because of the extra width on the edge side that part of the habaki is also longer.
This should tell you that the nakago-ana in your tsuba needs also to be offset and not exactly centred top to bottom on the seppa-dai oval.

IMG_0956.JPG


This is a template for a tsuba with an exact cross-section of a specific sword (based on the measurements the client provided) positioned in the proposed nakago-ana. Notice how the sides of the sword tang are given clearance. This is to ensure that when mounted the tsuba doesn't rub on the tang and thereby damage any inscriptions, or on older blades damage the patina. The blade will be secured by means of copper insets only at top and bottom. These inserts are called 'seki-gane' and are usually made from copper.

IMG_1029.JPG


This image shows the same nakago template placed alongside the nakago-ana. The copper backing plate represents the actual habaki that will be fitted to that blade. The habaki's fit into the saya (scabbard) is what will ultimately determine the correct position of the oval of the seppa-dai.

IMG_1030.JPG


And here the habaki template is placed back in the nakago-ana (blade template now into the opening from the front) to reveal the exact position and space the habaki will need when mounted on the seppa-dai. Or to be more precice, on the seppa on the seppa-dai. ;)

IMG_1031.JPG


Finally the outline of the saya around the habaki, positioned so that enough wood/horn is around the habaki to ensure a secure fit and that nowhere is it too thin. This oval now represents the scabbard's mouth but on the other side of the tsuba it allows for the fuchi that defines the alignment of the handle to be accurately lined up.

IMG_1032.JPG


And the sword nakago template positioned so that you can see its position clearly now relative the the seppa-dai. That nakago/tang template is what must inform where the tsuba's nakago-ana must be. The extra gap at the to is not important really at this stage because later both the top and bottom would be opening up to accept the copper inserts. If you examine the positioning of the horizontal scribed lines you may find some helpful guides.

IMG_1033.JPG


I'll add some comments regarding the correct positioning of the seppa-dai on the tsuba shortly. And then we need to discuss kozuka and kogai hitsu :?
"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: The fundamentals of tsuba design

Postby cam_hardiman » Tue May 30, 2017 11:04 pm

Very informative Ford. Thank you.
User avatar
cam_hardiman
Registered User
Registered User
 
Posts: 85
Images: 0
Joined: Sun May 14, 2017 12:09 pm
Has thanked: 11 times
Been thanked: 22 times

Re: The fundamentals of tsuba design

Postby Chris A » Wed May 31, 2017 9:37 am

Thank you Ford, for those of us who have never handled any Japanese sword let alone assembled one, it clarifies why things are as they are. :bulb:
'If I see further it is by standing on the shoulders of giants' - Newton
User avatar
Chris A
Sponsor
Sponsor
 
Posts: 141
Joined: Wed May 13, 2015 1:07 pm
Location: East Riding of Yorkshire , England
Has thanked: 1 time
Been thanked: 30 times

Re: The fundamentals of tsuba design

Postby Marcus » Wed May 31, 2017 3:26 pm

Thanks you Ford! As usual a great amount of information packed into this little thread. :)
Cheers,
Marcus :biggrin:
User avatar
Marcus
Sponsor
Sponsor
 
Posts: 704
Joined: Wed Feb 18, 2009 6:02 pm
Location: Paw Paw, Michigan USA
Has thanked: 22 times
Been thanked: 44 times

Re: The fundamentals of tsuba design

Postby Ford » Tue Jun 06, 2017 7:38 am

Time to talk about those little openings on either side of the seppa-dai on a tsuba. As a pair the openings are called Ryohitsu. Hitsu means opening or hole. So we have a kozuka hitsu and a kogai hitsu.
You'll occasionally see various 'non-standard' shapes but the most common are a sort of flat sided bean shape for the kozuka and a three lobed form for the kogai.

Viewed from the front, the side of the tsuba seen when worn in the obi, the kozuka is on the left and the kogai on the right.
Metal colour samples-28.jpg


Note how both openings just cut into the seppa-dai area. If you look at the images below of the slots on the saya that recieve the kogai and kozuka this accomodation should now make sense. Consider that if the openings in the tsuba are too far away from the seppadai how that means the angle at which the kogai or kozuka is steeper and this makes cutting the recieving slot in the saya (scabbard) difficult or impossible. This is why poorly positioned, or improperly understood, ryohitsu can reveal fakes or make contemporary tsuba look 'wrong' or non-functional.

Kozuka slot.
Metal colour samples-42.jpg

Kogai slot.
Metal colour samples-75.jpg

Note the gentle slope of the slots.
Metal colour samples-16.jpg


Sometimes only the kozuka opening is present but as a rule the kogai opening is not seen on its own.

These images show actual ryo hitsu from a number of Edo period tsuba from different schools. I've selected these as general examples of what I would consider to be orthodox or standard shapes and positionings.
In general you'll see that the inner edge is not quite flat but while it does have a slight curve to it never the less feels more defined or 'fixed' that the outer edge of the opening. Think of that flatter side as being the functional side in that that is where the back of the kozuka or kogai must rest and pass when withdrawn from the saya.

drangon_archer_0320.jpg
drangon_archer_0320.jpg (31.69 KiB) Viewed 1330 times

sc108098.fpx&obj=iip,1.jpg
sc108098.fpx&obj=iip,1.jpg (9.89 KiB) Viewed 1330 times

sc108129.fpx&obj=iip,1.jpg
sc108129.fpx&obj=iip,1.jpg (6.56 KiB) Viewed 1330 times

sc108148.fpx&obj=iip,1.jpg
sc108148.fpx&obj=iip,1.jpg (6.31 KiB) Viewed 1330 times

sc108183.fpx&obj=iip,1.jpg
sc108183.fpx&obj=iip,1.jpg (16.48 KiB) Viewed 1330 times


In the next installment we'll have a look at the varieties of less conventional shapes that were used in the past as well as plugging unused hitsu and how to fit protective liners on iron tsuba.
"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: The fundamentals of tsuba design

Postby cam_hardiman » Tue Jun 06, 2017 10:54 am

Another informative post Ford. I am looking forward to reading the next one.

Cam
User avatar
cam_hardiman
Registered User
Registered User
 
Posts: 85
Images: 0
Joined: Sun May 14, 2017 12:09 pm
Has thanked: 11 times
Been thanked: 22 times

Re: The fundamentals of tsuba design

Postby Ford » Tue Jun 06, 2017 1:31 pm

This template shows how the ryohitsu are placed in relation to the horizontal centre line running through the seppa-dai. The measurements reveal how they are ever so slightly lower. Notice also how the lower half of each opening is also just a tiny bit fatter. This is the provide a visual weight to the shape so that it doesn't look top heavy.

It is for the same reason, visual weight, that the seppa-dai is slightly lower than the centre of the tsuba.

These measurements are merely ones I settled on on this particular tsuba template and are provided only as a guide. I'm not suggesting these are fixed rules or that you MUST adhere to them :shock: They are just there to help illustrate the points I'm making. 8)
And as with anything I've posted on the forum feel free to use the template. The nakago-ana isn't too bad either ;)
Double click to see it extra large.
IMG_1113.jpg

The seppa-dai is 41mm long. A decent size for a contemporary katana. Higo seppa-dai tend to be somewhat larger than the actual seppa and fuchi.
"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: The fundamentals of tsuba design

Postby Michael T H » Tue Jun 06, 2017 6:05 pm

Amazing, but not surprising, how many things must be taken into consideration for the seemingly simple placement of the nakago-ana. Fascinating!
Looking forward to following along!
Michael H.
User avatar
Michael T H
Registered User
Registered User
 
Posts: 9
Images: 17
Joined: Thu Jan 21, 2016 5:12 am
Has thanked: 0 time
Been thanked: 5 times

Re: The fundamentals of tsuba design

Postby cam_hardiman » Mon Jun 26, 2017 10:47 am

On what occasions would there be no kozuka hitsu or kogai hitsu. Or only one of them?

Cam
User avatar
cam_hardiman
Registered User
Registered User
 
Posts: 85
Images: 0
Joined: Sun May 14, 2017 12:09 pm
Has thanked: 11 times
Been thanked: 22 times

Re: The fundamentals of tsuba design

Postby Chris A » Mon Jun 26, 2017 12:15 pm

I would think to suit the customer's requirements.
'If I see further it is by standing on the shoulders of giants' - Newton
User avatar
Chris A
Sponsor
Sponsor
 
Posts: 141
Joined: Wed May 13, 2015 1:07 pm
Location: East Riding of Yorkshire , England
Has thanked: 1 time
Been thanked: 30 times

Re: The fundamentals of tsuba design

Postby cam_hardiman » Mon Jun 26, 2017 1:06 pm

Chris A wrote:I would think to suit the customer's requirements.


Sounds like a pretty good reason.

Cam
User avatar
cam_hardiman
Registered User
Registered User
 
Posts: 85
Images: 0
Joined: Sun May 14, 2017 12:09 pm
Has thanked: 11 times
Been thanked: 22 times

Re: The fundamentals of tsuba design

Postby Ford » Mon Jun 26, 2017 2:31 pm

Generally speaking where we find both openings it would be on a wakizashi. Katana tend more often to have been mounted with only the kozuka. An exception was during the Tensho Period (1572-1592) when a single kogai was used on a long sword.
And some swords had neither.

It's generally accepted that the kogai is the older of the two accessories.

But as with all things Nihonto there are probably as many exceptions as examples.
"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: The fundamentals of tsuba design

Postby cam_hardiman » Mon Jun 26, 2017 2:36 pm

Thanks Ford.

Cam
User avatar
cam_hardiman
Registered User
Registered User
 
Posts: 85
Images: 0
Joined: Sun May 14, 2017 12:09 pm
Has thanked: 11 times
Been thanked: 22 times

Re: The fundamentals of tsuba design

Postby Ford » Mon Jul 03, 2017 11:53 am

Here's your next instalment. I hope this short film clip provides some further insights into good form in terms of the fittings but also filing techniques.

I've uploaded it in HD so if you have the bandwidth you can select a higher resolution. It will auto play at 720p but it's also got 1080p in there.

"The artist yields often to the stimuli of materials that will transmit his spirit." Odilon Redon
my website
User avatar
Ford
Administrator
Administrator
 
Posts: 4869
Joined: Mon Mar 10, 2008 10:30 am
Location: Torquay, 'The English Riviera', Devon, England.
Has thanked: 217 times
Been thanked: 211 times

Re: The fundamentals of tsuba design

Postby cam_hardiman » Mon Jul 03, 2017 12:18 pm

A great video Ford. Very informative, thanks for posting.

Yes, you do spoil us.

Cam
User avatar
cam_hardiman
Registered User
Registered User
 
Posts: 85
Images: 0
Joined: Sun May 14, 2017 12:09 pm
Has thanked: 11 times
Been thanked: 22 times

Next

Return to Technique & Tutorials

Who is online

Users browsing this forum: No registered users and 1 guest