I showed my husband a video of the Sashiko machine and he did a whole bunch of research on it. He said the problem with the way it sews is it does a chain stitch on the bottom, so if the thread breaks, the whole thing unravels. Also, there is only one thread - the bobbin thread. It is brought up to the top to make the stitch. Makes you wonder how often you have to put in a new bobbin.