Abstract: A bed sheet system for application to a mattress having rounded corners, a nominal mattress width between opposite sides of mattress, a nominal mattress length between opposite ends of the mattress, and a nominal mattress height. The bed sheet system includes a bottom flat fitted sheet and standard dimension top unfitted sheet. The unfitted top sheet may be attached by fastening along the foot-hem to the bottom sheet, or not attached with placement head-mark and size-mark, and corners marks to guide properly centered position with proper amount overhang on the sides and ends.