Flag of Indonesia

Republic of Indonesia

Names	Sang Saka Merah-Putih, Bendera Merah-Putih or Merah-Putih
Use	National flag and ensign
Proportion	2:3
Adopted	17 August 1945 (Original) 17 August 1950 (Official)
Design	A horizontal bicolour of red and white
Variant flag of Republic of Indonesia
Name	Ular-Ular Perang (Naval Jack)
Use	Naval ensign

The Flag of Indonesia is a simple bicolour with two equal horizontal bands, red (top) and white (bottom) with an overall ratio of 2:3. It was introduced and hoisted in public at the Indonesian Independence declaration ceremony on 17 August 1945 in Pegangsaan Timur street and Independence from the Netherlands on 17 August 1950. The design of the flag has remained the same since.

The Naval Jack of Indonesia is reserved for sole use by the Indonesian Navy. It flies from every active Indonesian war ship mast. The design of the jack is described as nine alternating stripes of red and white. It is nicknamed Ular-ular Perang (War Pennant or literally "War Snakes"), probably due to the stripes' design. The naval jack dates to the age of Majapahit Empire. The Majapahit Empire, renowned for its great maritime strength, flew similar jacks on its vessels.

Its colours are derived from the banner of the 13th century Majapahit Empire. However it was suggested that the reverence for the colours red and white can trace its origin to older common Austronesian mythology of Mother Earth and Father Sky; both symbolise in colours red (earth) and white (sky). This is one of the reasons why the colours red and white appear in many of the flags throughout Austronesia — from Tahiti to Indonesia and Madagascar. White and Red would also later on symbolise the duality of nature. The earliest record of the use of red and white panji or pataka (long flag along curved bamboo pole) were written in Pararaton; according to this source, the troops of Jayakatwang from Gelang-gelang hoisted the red and white banner during their invasion to Singhasari. This suggested that even before Majapahit era, the red and white colours already revered and used as kingdom's banner since Kediri era. The application of red and white textile colouring is available in ancient Indonesia. White is the natural colour of woven cotton fabrics, while red is one of the earliest natural dye discovered by native acquired from the teak leaves, the flowers of Averrhoa bilimbi or the skin of mangosteen fruits.