Sashiko Math Bag

Sashiko refers to Japanese embroidery or hand-stitching used to reinforce already-patched clothing around points of wear, but would also make the clothing or fabric stronger. Math (i.e., geometry) is embedded in most sashiko designs.

For this project, students will learn about the history of sashiko, apply math concepts using the designs, use computer software to create sashiko inspired designs, draw designs on a 5" x 5" grid, and use hand stitching to sew designs on fabric. Students will learn how to make and stitch two designs (squares), and sew the squares together to make a small bag or pouch.

Note: This project is for grades 3-8+.

Black or blue burlap squares with finished edges

Hand stitching thread

Hand stitching needles

Scissors

White chalk pencils (other colors optional)

Standard rulers

Watch a video about the origins of sashiko such as this one: https://www.bbc.com/reel/video/p0gl796s/japanese-sashiko-the-art-of-stitching-stories

Sashiko hand-stitching creates different types of lines that form geometric patterns. Exercises and word problems can help improve the skills of students in grades 3 - 8 to identify and differentiate between parallel, perpendicular and intersecting lines using sashiko.

Use the attached PDFs to teach students how to identify these math concepts in sashiko designs and patterns.

As an extended activity students can practice hand stitching the different lines, esp. using the running stitch method.

Many sashiko designs are algorithmic, meaning they can be created using a set of predefined rules that tell a computer program what to do. Students can use a CSDT or culturally situated design tool to simulate sashiko patterns. CSDTs are web-based software applications that allow students to create simulations of cultural arts. The CSDT students will use for this project was built based on the Snap! programming language.

To use the tool, follow these steps and refer to the images:

1. Visit the CSDT website, specifically the section on Afrofuturism at: https://csdt.org/culture/afrofuturism/software.html
2. Click on the "Nontsi" button to launch the CSDT software (there are tutorials on the website)
3. Edit the demo block code (ex. remove sound blocks, rearrange and modify block parameters)
4. Click on the "Costumes" tab, then import square design as a 200 x 200 pixel PNG file (see quick reference guide)
5. Run the code by clicking on the green flag
6. Keep adjusting and modifying the block code as needed until there are 5 rows and 5 columns (see image).

Note: the bottom of the finished CSDT-generated design will be cropped because the window is not square.

For this step, students will need to print out, then draw their CSDT-generated designs on black burlap squares. Draw 5" x 5" grids on the fabric squares using white chalk pencils and rulers.

Optional: Use two or more chalk pencil colors (one color for each set of lines).

Note: Younger students (and non-sewing people) can draw their designs on paper grids or fabric, using colored pencils or markers. They can also color in their designs using pencils/markers.

Once students draw their grids/designs with chalk on burlap fabric squares they can use a running stitching to sew the lines into the fabric:

• Use a needle that can accommodate your thread’s thickness. Hand stitching needles and thread are recommended.
• Unspool at least 1 foot (30 cm) of thread and trim the end for a clean cut.
• Insert the end of the thread through the eye of the needle (if the eye is bigger this step is easy)
• Pull the thread through the needle to create a tail. 
• Knot one end and leave the other end shorter.

Note: If students want to create a pouch or bag they may want to stitch designs on two fabric squares (front, back).

General running stitch steps:

1. Push a threaded needle through the fabric from the back.
2. Next, push the needle back down through the fabric next to where you just came up, then pull the thread through the fabric to complete the stitch.
3. Push the needle back up through the fabric, leaving a space from the previous stitch. Then push the needle back down through the fabric again making a second stitch.
4. Continue step 3 until the stitch is complete.

Stitch/sew the two fabric squares together along three edges using a running stitch or blanket stitch (see images). Leave the fourth edge open to make the pouch. Some general steps for blanket stitching is as follows:

1. Place the right-sides of the felt layers together. Burlap has a very loose weave and is thin, so the needle should go through both layers easily.
2. Knot one end of the thread.
3. Push the threaded needle from the topside of the first layer through to the bottom side (second layer).
4. Flip both sides/layers around and insert the needle to the left of where the thread is coming out.
5. Pull the thread through most of the way, then put the needle through the loop from the back to the front (see image) and pull it tight.
6. Insert the needle to the left of the last stitch.
7. Pull the thread through most of the way, then put your needle through the loop from the back to the front, then pull it tight.
8. Repeat steps 6-7 across the edge(s) until finished and make sure to make a knot next to where the last stitch is.

Once all three edges are stitched/sewn add a strap (optional) and add items of your choice to your new pouch.

This project is an artifact of Culturally Relevant Math Expressions created with Lesley STEAM Learning Lab at Lesley University and made possible by the generous support of Takeda US CSR & Philanthropy.