Shawl Geometry: Right Triangle

This is the fourth post (out of 15) in a series about different shawl shapes and how to knit them. The introduction post, which lays out the game plan can be found… thisaway.


Right Triangle Top Down

The traditional right triangular shawl is simply half of the center out square.

Increase 4 stitches every other row: one at the right edge, two along the center back to create a “spine,” and one on the left edge.
Triangle Top Down

CO 5 sts.
R1: K1, yo, k1, yo, pm, k1, pm, yo, k1, yo, k1.
R2: P across.
R3: K1, yo, k to marker, yo, sm, k1, sm, yo, k to last stitch, yo, k1.
R4: P across.
Repeat R3&4.


Right Triangle Bottom Up

Just like the square, the triangle can be worked from the center out and the hem in, this triangle can be worked from the top down or the bottom up. This makes sense since this triangle is simply half a square.

Triangle Bottom Up

Cast on stitches for your hem, then decrease 4 stitches every other row: one at the right edge, two along the center back to create a “spine,” and one at the left edge.

Determine your gauge, and how deep you want your shawl.
1. [depth of shawl] / 2 = Z
2. [Z] x [1.4142] = [magic number]
3. [magic number] x [rows per inch] = [number of rows total]
4. [number of rows total] / 2 = [number of decrease rows] you divide this by two because you decrease every other row
5. [number of decrease rows] x [4 stitches decreased per decrease row] = [number of stitches decreased]
6. [number of stitches decreased] + [5 bind off stitches] = [number of stitches to cast on]
Make this number a whole number that is divisible by 4.

Then you cast on your hem stitches, marking the center stitch with a marker on either side.
R1: Ssk, k to 2 sts before marker, ssk, sm, k1, sm, k2tog, k to last 2 sts, k2tog.
R2: P across.
Repeat R1&2.


Both of these methods create shawls that are half squares and right triangles. Some people find these a little bit hard to wear in that they slide off the shoulders and are therefore a little bit fiddly. So over the next two weeks we’ll talk about two variations that I think are a little easier to wear, a shallow triangle (next week) and a right triangle with “wings” (the week after next.)

These are simply the basics, backwards and forwards. These basics can then be manipulated and expanded upon and played with to create a myriad of other shawl shapes. However, these shapes are incredibly powerful on their own, add patterns & textures, lace, cables, knits/purls, color work, anything you can think of.

The books this series spawned:
Shawl Geometry I: the math of shaping shawls for non mathy people
Shawl Geometry II: 16 more shawl shapes to design and play with
Shawl Geometry III: the relationships behind the numbers


The previous post: Circle with Concentric Circles of Increases
The next post: Shallow Triangles

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