Sudare was made to shield against the sun, with small openings between the bamboo strips, so that the air flow wasn't affected, but the dust was filtered, and the insects were kept out. When sudare wasn't used, it was rolled up the same way as the window blinds. Interestingly, sudare are still in used today, in the traditional areas, as you can see in today's photo, taken in Kurashiki.
EXIF info:
Nikon D90
Lens: 18-70mm F/3.5-4.5G
Focal Length: 22mm
Aperture: F/5.6
Shutter Speed: 1/800s
ISO Sensitivity: ISO 200