The Asian country whose flag is a horizontal bicolor of red over white is Indonesia.
Indonesia’s national flag consists of two equal horizontal bands: red on top and white below. Its proportions are 2:3, and the design has remained unchanged since independence. In Indonesian, the flag is commonly called Sang Saka Merah-Putih or simply Merah-Putih, meaning “red-white.”
The flag was publicly raised during Indonesia’s proclamation of independence on 17 August 1945 in Jakarta. It was later used again during the Dutch transfer of sovereignty on 27 December 1949. Indonesia officially adopted the flag on 17 August 1950, after the country’s constitutional arrangements were established.
Red and white have older roots in the region. The colors are associated with the Majapahit Empire, whose symbolism helped inspire modern Indonesian nationalism. The design is an easy source of confusion because Monaco’s flag is also red over white, while Poland’s is white over red. The countries’ flags differ chiefly in proportions and, for Poland, the reversed arrangement.