"Inset dc filet crochet" is my name for the stitch. I don't know if it has a 'real', established name. I first leart this stitch in a fully Japanese crochet book without a word of English. It's a lovely and versatile stitch but to me, nameless.
It makes use of 2 yarns - one for the "inset" part and the main working yarn is exactly like double crochet filet crochet -- hence my name "inset dc filet crochet".
Here is my shortie, quickie video tut on how to work the "inset dc filet crochet" stitch.
