National Flag of Nepal: Geometry, Construction and Meaning

Nepal has the only non-rectangular national flag in the world. Every other sovereign state flies a four-sided banner; Nepal's is a five-sided figure formed by two triangular pennants stacked one above the other, a shape vexillologists call a 'double-pennon'. It is also the only national flag that is taller than it is wide, which is why it looks so distinctive on a wall of flags at the United Nations or the Olympics.

The shape is not a modern novelty. Triangular war banners were common across South Asia for centuries because a narrow pennant furls and flutters even in the lightest wind, keeping it visible over long distances on hills and battlefields. The flag of the old Gorkha kingdom began as a single crimson triangular banner of the Shah kings carrying various deities and symbols. Nepal simply never switched to the rectangular European format that most of the world adopted.

The present two-triangle form is usually traced to the era of King Prithvi Narayan Shah, who unified Nepal's small principalities in the eighteenth century, after which the double-pennon became the standard national banner. The two juxtaposed pennants are widely said to represent rival branches of the ruling dynasty whose separate single pennants were later joined, and popularly the two peaks are read as a symbol of the Himalaya and of Nepal's two great faiths, Hinduism and Buddhism.

The field of the flag is crimson (Nepali: simrik), the national colour of Nepal. Crimson stands for the bravery and martial spirit of the Nepali people, and it is also the colour of the rhododendron (lali gurans), the national flower. This deep red is the dominant impression the flag gives.

Framing the crimson on every side is a deep-blue border. Blue represents peace and harmony, and its placement all around the red is often read symbolically: that Nepali bravery is, on all sides, bound and tempered by a desire for peace. The two celestial emblems inside the flag are white.

The upper pennant carries a white crescent moon; the lower pennant carries a white sun. In official and popular readings the moon signifies calm, the cool climate of the Himalayan highlands and the hope for permanence, while the twelve-rayed sun signifies fierce energy, hard work and the warm climate of the southern plains. A common further interpretation is that the two bodies express the hope that Nepal will endure as long as the sun and the moon. Older explanations also link the moon and sun to the lunar and solar lineages of the Rana and Shah houses.

Until 1962 both the sun and the crescent moon carried stylised human faces. These faces were removed when the flag was standardised, giving the clean geometric emblems seen today. The moon shows eight rays and the sun shows twelve rays.

For most of the nineteenth and twentieth centuries Nepal flew triangular pennants derived from Shah and Rana usage, and the twin-pennant design took hold as the national standard after unification. During the Rana period the celestial emblems were shown with human faces, reflecting the dynasty's claimed solar and lunar descent.

The flag was given its precise, legally standardised form on 16 December 1962 (Poush 1, 2019 BS), alongside a new constitution. At the request of King Mahendra, the civil engineer Shankar Nath Rimal fixed the exact geometry, and the human faces on the sun and moon were removed to modernise the design. That 1962 mathematical definition is the direct ancestor of the construction method still in force today.

The current legal basis is the Constitution of Nepal 2015 (2072 BS). Article 8 designates the flag, and its exact shape and drawing method are set out in Schedule 1 (Anusuchi 1). The Schedule not only describes the flag but prescribes a full ruler-and-compass construction, so the flag is one of the very few in the world whose geometry is written into the supreme law rather than merely into a specification sheet.

Schedule 1 tells you to build the crimson shape first (without the border), then add the moon, then the sun, and finally wrap the blue border around the whole figure. Many of the guide lines and circles used in the process are described as 'imaginary' and are not drawn on the finished flag. The steps below follow the constitutional method using its own point labels (A, B, C, and so on).

Making the shape inside the border: On the lower part of a crimson cloth draw a horizontal line AB of the required length. From A draw AC perpendicular to AB, with AC equal to AB plus one-third of AB. On AC mark off D so that AD equals AB, and join B to D. On BD mark off E so that BE equals AB. Through E draw a line FG parallel to AB, starting from point F on AC, with FG equal to AB, then join C to G. This produces the two-triangle outline of the red field.

Making the moon: Mark AH on AB equal to one-fourth of AB and draw HI parallel to AC. Bisect CF at J and draw JK parallel to AB meeting CG at K; L is where JK crosses HI. Join J to G; M is where JG crosses HI. Using centres L, M, N and T with the radii defined in the Schedule, draw the semicircles and arcs that shape the crescent, and place eight equal triangles (rays) in the space inside the semicircle so the moon shows eight rays.

Making the sun and the border: Bisect AF at U and draw UV parallel to AB meeting BE at V. With the centre and radii the Schedule defines, draw the inner and outer circles of the sun and fill the ring between them with twelve equal triangles, giving the twelve-rayed sun. Finally add the deep-blue border of width equal to TN on all sides of the flag; the Schedule notes the border and the fixing holes are handled slightly differently depending on whether the flag is tied with rope or fixed to a pole.

Because the flag is built by construction rather than by a fixed width-to-height rule, its proportions come out of the geometry itself. The bounding rectangle of the crimson field alone has a simple 3:4 shape, since AC is defined as AB plus one-third of AB (that is, four-thirds of AB).

Once the deep-blue border is added around the finished red figure, the overall proportion is no longer a neat whole-number ratio. The ratio of the flag's height to its greatest width works out to an irrational number, approximately 1.219 to 1 (roughly a width-to-height ratio of about 1 : 1.219). Nepal is therefore unusual not just in shape but in having a national flag whose official aspect ratio is an irrational number derived from its constitutional construction.

The colours themselves are described by name in the Constitution (crimson field, deep-blue border, white emblems) rather than by printing codes. Commonly used approximate values are crimson around hex #DC143C and blue around hex #003893 with white emblems, but these Pantone, RGB and CMYK figures are conveniences derived by third parties, not exact values fixed in Schedule 1.

The national flag is one of Nepal's constitutionally protected state symbols, alongside the national anthem, coat of arms, the rhododendron as national flower, the crimson national colour, the cow as national animal and the lophophorus (danphe) as national bird. Article 8 of the Constitution of Nepal 2015 names the flag and points to Schedule 1 for its exact form.

For students and Loksewa (public service commission) candidates, the flag is a standard exam topic: expect questions on why it is triangular, the meaning of its colours and emblems, the number of rays on the sun and moon, and the fact that it is the world's only non-quadrilateral national flag. Knowing that the construction lives in Schedule 1 and that the red field is a 3:4 figure is often enough to answer these confidently.

In everyday use the flag flies over government offices, schools, embassies and homes, and appears on the jerseys, kit and banners of Nepali teams and climbers. Its silhouette is instantly recognisable worldwide precisely because no other country shares its shape, making it a compact and powerful emblem of Nepal's identity.