Flags with Circles & Discs
Circular solar, lunar, and polar emblems placed on solid or bicolor fields, including Japan, Bangladesh, Palau, Greenland, and the 1870 Meiji merchant flag.
Construction & geometry note: Vexillologists compare disc flags by diameter-to-hoist ratio (usually 3/5 or 2/3 of the height) and whether the center is strictly bisected or shifted toward the hoist.