Flags with Diagonal Designs

Diagonal flags are a relatively modern invention, almost entirely a product of twentieth-century decolonization. Where stripes and crosses lock the eye into stable horizontal or vertical reading, a diagonal band suggests motion, division, or the sweep of a horizon — themes well suited to nations defining themselves at independence.

Tanzania's flag, adopted in 1964 to mark the union of Tanganyika and Zanzibar, uses a black diagonal stripe to literally bridge the two former colonies' colors. Many other diagonal flags carry similar symbolism.

The Democratic Republic of the Congo's yellow band cuts across a sky-blue field as a marker of national unity, while the Republic of the Congo, Trinidad and Tobago, and Namibia all use diagonals to represent rivers, the equator, or paths to nationhood. Pacific nations including the Solomon Islands, Marshall Islands, and Papua New Guinea favor diagonals because the angled line reads naturally as the horizon at sea, rooting each flag in the maritime geography of its people.