Oh Sew Cultured: Tutorial: A top made only from triangles!

Introduction

I mentioned in a previous post that I was thinking of doing a tutorial on the Pinterest mainstay sunshine yellow triangle top, which seems to be taken from 'Clothes by Yoshiki Hishinuma' (1986). You know I love me some twisty japanese clothing.

I made a second version of the top for this tutorial, and honestly I think I like it more than the first version.

Before we jump into it, I just want to say that I think there's quite a few tutorials and instructions out there for a sleeveless t-shirt based on a similar type of pattern. What sets this one apart is the sleeves. If you look closely at the image of the original, you can see they're gathered at the wrist, forcing them to twist, which is completely weird. So this tutorial shows you how to get a proper twitsty triangle sleeve on your Japanese triangle top.

You will need:

Basic measuring, drawing and sewing supplies
Sewing machine or overlocker or mad hand sewing skillz
Loose drapey knit fabric (those ones with poor recovery i.e. no elastane work!)
Something to finish the edges (e.g. Fold over elastic, self-fabric bands, knit binding, cuffing/ribbing, added hem allowance)
Mannequin, or some other draping aid
Some floor space/some table space

Pattern

The basic pattern is 2 different triangles (cut 2 body, cut 2 arms)

The original top seems to use all-equilateral triangles (which give elbow-length sleeves), but I've also written up instructions here for isosceles triangle sleeve pieces which gives you full-length sleeves.

Taking measurements, drawing the pattern

I drafted these pieces by folding the paper in half lengthways and drawing one half of the pattern. Once cut out and once unfolded, I had the full pattern piece. You can use whatever drafting method suits you.

Bodice:

The front and back pattern pieces are identical.

Measure your hip circumference and the length between the nape of your neck and your hip. Draft an equilateral triangle (sides all the same length) that uses an average of these measurements.

For reference, my mannequin is an 8-10UK, my hips measure about 37" (94cm) at their widest. They are probably a bit smaller at high hip. ****** The sides of my bodice triangle measured 34" (88cm).

You can break out your classroom trigonometry skills to check that the hip measurement and vertical length nape>hip are similar enough that it suits your needs. (You will probably need to fiddle numbers and compromise a bit - it's not a perfectly fitting top). Just make sure you end up with an equilateral triangle pattern piece.

If maths isn't your jam and you prefer the Micarah Trewers approach to pattern drafting, measure from the nape of your neck to the centre front top of your trousers/skirt/underpants. Draw 3 lines directly on the fabric (preferably in pancake batter).

Elbow-length Sleeves:

Draft an equilateral triangle, with sides equal to half of the side length of the bodice triangle. E.g. If your bodice piece has sides of 88cm length each, your sleeve piece will have sides of 44cm length each.

Full-length Sleeves:

Draft an isosceles triangle, where one side is equal to half of the length of the bodice sides. E.g. If your bodice piece has sides of 88cm length each, your sleeve piece will have one side of 44cm length. Then measure from your armpit to your wrist. Note this number. Measure around your wrist or measure a stretchy cuff on an item of clothing you already own. Note this number. Add these two numbers together, this is the length of each of the remaining two sides of your isosceles triangle. Draft the triangle.

You can add seam allowance either on the paper pattern pieces or directly on the fabric - just be sure to know which one you're doing!

Don't notch anything yet - especially not if you're doing the all-equilateral version of the top. It is incredibly confusing and unhelpful.

Cutting the fabric

This top is a good opportunity to mess around with stripes and pattern placement, or you can keep it standard if you like. On my first version, I cut one bodice piece at 90deg rotated so that the stripes on my shoulders would look interesting.

Once you've cut out the fabric you will end up with 4 pieces. Lay them out flat

Assembling the top

Take each body piece and mark Centre Front/Centre Back with a notch.

With right sides together, pin the body pieces together at top and bottom of the garment (align the CB/CF notch with the point on the other piece.) It will look like this:

Fold over the "shoulders" of the triangle, right sides together, and pin the seams together. This is the front of your top.

Carefully flip the mass of fabric and pins over, it's time to pin the back of the top....(or flip it recklessly, I'm not judging you!)

Fold the outermost points to the CB so they meet in the middle of the back hipline, pin the seams together. Right sides are still together. Baste if desired. Remove the pin at the CB point so the hemline is "open" and you have a way in to the top.

You will notice that we effectively closed up the neckline with pins. Now is a good time to decide what your neckline looks like. Use a dressform if you have one available as a draping aid, or a pillow, maybe a cardboard cutout. Currently the point of the front triangle sits at the top of the mannequin's head/neck stump.

Drape something you like for the neckline and finish it off. The original has the neckline along a side of the front triangle, but you could do something else, or even trim the triangles to taste. Leaving the neckline raw is also an option, just make sure you have a space to put your head through.

Remember that the top is currently inside out and you may screw up like me and put the neck slit on the wrong side. Double check before slicing or stitching anything.

You may find it helpful to stitch one or both of your shoulder seams first. It all depends on your neckline finish. On my first version I added a band to each edge, so it was added flat to each pattern piece. On my second version I stitched one shoulder seam, added the collar and then stitched the other one closed.

Lay out flat again, remove the pins from the body seam (diagonal seam from armpit to CB hip) to make it easier to lay flat.

Take the arm pieces and position them on either side of the bodice. Pin them in place (right sides together). Stitch.

Mark both sides of the sleeve triangle tips with your wrist/cuff measurement.

Technically you only need to do this for the front edge of the sleeves, but (like me) you will probably mess this up and it'll be easier to just mark both edges.

Put the top on your mannequin or lay out flat so you can clearly see front from back.

On each sleeve, finish the wrist area. It is on the front edge, between the notch you've just cut and the point of the pattern piece.

On my v1 I stitched a 1" band like the neckline. On my v2 I was planning to fold over and topstitch, but I made a last minute decision to use the leftover ribbing/cuff material from the collar. This looks nice but added about 7cm to the total length of the sleeve. If you're adding a cuff, you might want to account for the extra length when you're drafting the pattern.

Gather the whole length of the back edge of the sleeve seam (you could use elastic or gather with thread using your preferred technique) so that its length matches the length of front edge of the sleeve triangle.

Pin the two edges of the wrist opening together (right sides together). Pin the "underarm" seam, armpit to wrist, easing and arranging your gathers. If you're making the elbow-length sleeves it will look a bit puffy and twisty. If you're making the full-length sleeves, it will look really cursed. Stitch the "underarm" seam.

(re)Pin and stitch remaining body seam right sides together. It should be the diagonal line from armpit to CB hip. (diagonal line from armpit to CB hip).