I've been meaning to post about this for longer than you need to know!! I have put together a tutorial to make one of these obis. You need to find 3 co-ordinating fabrics (Fabric A plain and the Fabrics B & C with a print/pattern). Fabric D is for the backing and the feature strip around the centre, so choose something plain that will fray well (more on that later!)
The finished size for this pattern is 90cm. You might want to measure around your waist and extend or reduce it to fit. You want the obi to overlap very slightly (say 2cm) at the back. If you do need to extend or reduce the length, add/subtract the amount required to/from both fabrics 1A and 1B making sure they are both still 10cm wide.
Cut Seven pieces of fabric is per diagram. You will also require 2 pieces of sturdy ribbon (ie grosgrain) approx 2cm wide and 25cm longer than the size of your waist. These ribbons don't need to be the same colour, but should be the same fabric.
The seam allowance in this tutorial is 1cm.
With the right sides together sew 1A to 1B and 2B to 2A making sure that you swap around the order of the fabrics so fabric A is on top in one and Fabric B is one top on the other.
Again with the right sides together sew Pieces 1, 2 and 3 together.
Turn it over and place the Fabric strip (Piece 5) on the right side of the obi along the horizontal seam. Sew Fabric strip on leaving a 1cm allowance on each side. Pull out a few strands of the fabric to make it fray.
With the right sides together, pin the backing piece 4 to the obi. Stitch along the top and the bottom leaving the ends open. Once sewn, turn right side out.
Turn the ends in by 1cm and place the ribbons (one at each end) at the top of the obi and pin the ends together. Sew using the machine, or handstitch with invisible thread. Turn the ends of the ribbons over twice at the ends and hem them to stop fraying. Done!
Of course, if you don't have the patience to get the fabric, cut it up and sew it all together, you could hop over to my shop and buy one of them already made up!! In two different sizes and all completely different designs, you will be sure to have a one and only!