These fabrics are specially printed for hitomezashi (one stitch sashiko) designs by Olympus Thread Mfg. Co., Japan. I've nicknamed them 'just dots'! Instead of having to mark your fabric with an all over grid, these fabrics have dots at 5mm intervals for an easy foundation for your pattern and the marks wash out afterwards.
The dot fabric sold by the half metre is a sturdy sashiko cotton, ideal for all your hitomezashi projects. The hanafukin panels are printed on the same sarashi cotton fabric as all the other Olympus hanafukin sampler panels, so you can colour coordinate across the range.
Simpler patterns like kakinohanazashi (persimmon flower stitch) or komezashi (rice stitch) can be stitched without further marking, going dot to dot, and this video from Olympus gives a great tip for using the dots to mark more complex sashiko panels before starting to stitch.