A good to way to learn proper sword sugata, or silhouette, is to make a kata, or pattern, from 1.25-1.5mm thick sheet of mild steel. I bought a full sheet and cut it in about forty 5 cm wide bands of various lengths. The longest tachi won’t usually exceed 100 cm of zen-nagasa (full length, from tip to tang).
Nowadays there are various sources of printed oshigata and pictures available in books, exhibition catalogues or even on the net. One should only make patterns from healthy, typical-looking famous swords, for making a model out of a worn out or rarely seen sword shape is misleading at best.
The important point is that some sword measurements be clearly provided. I visit a local convenience store, buy a chocolate milk and spend fifteen minutes on the photocopier printing life-size sword tracings or photographs. For example, if a sword is indicated as measuring 82 cm, and its photograph has a “nagasa” of 41, I simply have to copy the image at 200%. I make sure to measure the printed version, but the machines have never been wrong so far (this is Japan!). Be careful when checking the haba because not everyone measures the width the same way. Some do so from ha-saki to mune-saki, while others stop at the mune-kado. Also, the mune’s apparent height on oshigata is usually wrong, and only provided for aesthetic purposes.
I actually post many of these life-size prints on my walls as a source of study and reference. I have early Kamakura tachi, some Muromachi tanto and katate-uchigatana, and then some of my favorites, like the 10th century Kogarasu-maru.
There are many techniques to make patterns, but I prefer to simply hold the photocopy onto the sheet metal with magnets, and mark dots with a sharp punch to outline the outer limits of the shape to be cut out. Give yourself some play as it’s easier to remove material than to put it back…
For longer swords, it’s a waste to use a wide piece just to be able to get the whole blade, so I curve the band by forging it (cold) on one side until the sword’s curvature fits in.
The real work starts after that, with grinders and files to fine tune the shape. The final pattern silhouette should be just as finely crafted as a finished’s swords, since any lack of proper reference or good work along the way is counter-productive to getting a good result at the very end. Moreover, it’s really good practice to learn and understand the fine details of a sword sugata. You come to better understand features such as funbari, the kissaki’s fukura, where the curvature actually lies, the nakago’s shape, etc.
Apprentices as asked to make as many kata as they can: these are eventually used for sword making, can be kept for a lifetime for reference and study, and their very making is a good and cheap source of practice. Sheet metal is a little more affordable than finely forged tatara-smelted steels!
For the blade to be made in the coming weeks — and probably for a short while after that too, I’ve decided to focus on the Muramasa school. I have a strange relationship with these smiths because I dislike most of the blades, but love the others! As most swordsmiths in the 16th, I believe that Muramasa was a workshop producing blades in small batches. The three generations always mentioned were simply the heads of the shop, but the actual craftsmen making the swords were more numerous. Because the shop wasn’t big enough, such as the Bizen or Mino ones, craftsmen were involved in different tasks depending on the work to be done. The quality of Muramasa blades were therefore varying greatly.
Mostly, I have chosen to focus on Muramasa for a while because their work is accessible. I find it pointless to try to make Ichimonji or Awataguchi blades with the standard-issue tamahagane, like trying to make fine sake with south-eastern asian rice. The materials and techniques are just too far apart, and the result meaningless. Let’s see what I can come up with.
In the mean time, you are invited to download printable tracings of a handful of blades. Among them the most famous tanto of all, the Aizu Shintogo by Shintogo Kunimitsu, supposedly the master of Masamune. it is printed on two pages and which then need to be joined. Make sure you application prints at 100% without “adjusting to paper size”.