Thursday, December 11 2014

9-strand Shigeuchi (繁打九つ組)

The most common sageo (mounting cord) for a katana is a 9-strand braid normally done on the takadai, but instructions for making it on a marudai are here (my own instructions on how to make it on a foam disk are here, in abbreviated form). After a little practice (and the acquisition of a set of 240-gram tama), I made a quite nice one for my primary iaito, using DMC embroidery floss (6x 4-meter strands) to get just the right color combination. It’s extremely quick and easy, especially if you follow Tada-sensei’s pictures and lift two tama at once.

Commercial Shigeuchi sageo are only found in two styles, solid and 2-strand zig-zag (221111111). The reason for this is that most of the other interlacements kind of suck. Shigeuchi is an oblique 2/2 twill pattern, and the progression of strands across the braid is much more regular than most kumihimo braids. Here’s the Carey diagram for the front side (the back is just a 180° rotation):

Carey Diagram for 9-strand Shigeuchi

As you can see, every strand follows the same ordering in every column, severely limiting the possibilities. In fact, the standard “clockwise from the top” numbering system obscures the regularity a bit; if you numbered the five strands on the right 1-5 from the top, and the four on the left 6-9 from the top, the numbers in the above diagram would all be in order, which quickly became obvious in my 9-color test braid.

Viable three-color patterns are even harder to find, and the only three I’ve found that are worth mentioning are 111113322 (double zig-zag), 113323332 (crossing double-zig-zag) and 111223332 (sort-of triple-zig-zag). I’m sure there are others, but my script didn’t do a good job of reducing the search space, leaving me with 674 GIFs to pick through.

[Update: three more 3-color patterns that have potential]

Here are the 29 two-color interlacements. It took a bit of work to get my script to correctly eliminate all of the duplicates, but I think I managed it this time without accidentally eliminating real patterns.

Next up: 17-strand Shigeuchi, which produces a very wide, soft, flat braid. The setup and braiding are very simple, and I prototyped it on the foam disk just to make sure I got it right. Going clockwise from the top, lay out your strands in groups of: 1, 2, 2, 2, 2, 1, 2, 2, 2, 1. To braid, lift 2 and 3 (left hand) and bring 1 under to below 5; lift 6 and 7 (right hand) and bring 1 under and across to below 10; lift 15 and 16 (right hand) and bring 17 under to below 13; lift 12 and 11 (left hand) and bring 17 under and across to below 9; reset. Try to keep the groups dispersed around the mirror, to keep the tension even.

If you have enough tamas and room on your marudai, you could add 8 more and bring it up to 25. Still not a lot of patterns, but it should be a very wide woven band. If you knocked together a Texas-sized marudai and bobbins, you could make a quite impressive scarf out of chunky yarn. (I’m thinking about it…)

[yes, there are scripts; pretty rough right now, but the pattern-drawing script reads the braid info from a config file, allowing me to color any Carey diagram composed only of rectangles; I need to add some more shapes to match her more complex diagrams. I’ll release them eventually.]