To work Japanese darning first work several rows of darning stitches in a brick pattern as below.
Next begin joining them with slanted stitches as follows. Working from right to left bring your needle up at 1, down at 2, up at again at 3 and down at 4. Repeat along your row.
Turn your work to stitch the row below in exactly the same way as before. Repeat joining each row to form a pattern or work separate rows as I have done.