It was quite different from what we know today, because the raw fish meat was covered in rice mixed with rice wine and was left to ferment. At the time of consumption the rice was thrown away and only the fish was consumed.
The first version of sushi as we know today appeared during the Edo period, in the capital city of Edo, in the form of nigiri-zushi, raw fish placed on shaped rice.
EXIF info:
Nikon Df
Lens: 24-70mm F/2.8G
Focal Length: 54mm
Aperture: F/3.5
Shutter Speed: 1/60s
ISO Sensitivity: ISO 2000