Gobosei (Pentagram) (五芒星)
Gobosei (Pentagram) is a figure consisting of five lines of equal length that are mutually intersected, and is one kind of star-shaped regular polygon. It is also known as Gobosei shape, five-pointed star shape, 五線星型, star-shaped pentagon, 正5/2角形. It is inscribed in regular pentagon, and is symmetrical. It is unicursal.
It has been used in all countries as a figure that can design five elements in parallel. It has been used as an occult mark throughout the world. Depending on the usage, it can be used as protection, or it can symbolize the devil, when it is placed upside down. When it is regarded as the symbol of the devil, it is sometimes called a devil star. Further, it is often used as a mark representing a star, because the outer five triangles are associated with the glitter of a star.
The shape without the inner small regular pentagon (five-pointed star) is often called Gobosei.
How to Draw
There are usually two directions to draw the Gobosei. One is to make one point upward (often called "upright pentagram, "as shown in the upper right figure. The other is to make the two points upward by rotating it by 36 degree (angle) (often called 'downward pentagram'). It is not constant in history which one is used, but the upright one has been more frequently used in recent years.
Further, a cultural meaning is added in the order of drawing.
Golden Ratio
In the figure, the ratio of length of blue line and red line, green line and blue line, and purple line and green line are equally 1 : 1+√5/2 = 1 : 1.168... This is equal to golden ratio.
Figures made with the golden ratio have been considered beautiful since ancient times. The Gobosei containing a number of golden ratios, in spite of its simplicity, was considered to be representative of beautiful figures.
Examples
Kastellet fortress in Denmark, Goryokaku in Hokkaido, and the municipal emblem of Nagasaki City are based on the Gobosei.
Onmyodo (way of Yin and Yang; occult divination system based on the Taoist theory of the five elements), and the Chinese Bellflower Crest of ABE no Seimei
In Onmyodo, the Gobosei has been handed down as the talisman to ward off evil spirits. The meaning contained in the mark is that it represents the rivalry of the functions of the five elements (wood, fire, earth, metal, and water) in Onmyo-gogyo-setsu (The Theory of Five Elements), which formed the basis of Onmyodo. The Gobosei was useful for ofuda (paper charm) to ward off all kinds of evils.
ABE no Seimei, Onmyoji (Master of Yin yang) in the Heian period in Japan used the crest of Gobosei as the symbol of Gogyo shiso (Five Elements Theory). As the crest looks like a Chinese bellflower, it is called the Seimei bellflower crest. It can be seen in the sacred emblem of Seimei-jinja Shrine even today. See Semandoman.
Imperial Japanese Army
A Gobosei was embroidered with gold line (silver line) on the top of the official cap of the military uniform (Imperial Japanese Army) formal attire (taireifuku [court dress, full-dress uniform]) that the under-officers put on as the formal attire or the ceremonial dress.
According to the "Army dress code system" (1900 imperial edict No. 364), the Gobosei was embroidered on the caps of the Imperial Army from taisho (general) to soldiers.
It is said to have been designed after the calyx of a cherry blossom or to have been adopted as a pun based on two possible meanings for "tamayoke" (written as "弾除け," it means bulletproof", but written as "多魔除け," it means "barrier against multiple evils"); however, the word's origin and exact meaning are unknown.
Furthermore, the army patch on the uniform for military campaigns that was worn by all the army civilian employees, including officials appointed by the emperor, was designed based on the Gobosei, and it was used as the official style (1943 style). In addition, the badge type (cloisonne) mark, worn when they were in business suit, used Gobosei.
Ancient West
Historically, it is identified the oldest use of the Gobosei was in the Mesopotamian books around 3000 B.C. It was called UB in Sumer. Further, the downward Gobosei was used as the pictogram representing 'corner, small space, hole,' and so on. As it represents a womb in Egypt, it is said it had a sexual meaning. In Babylonia, the forward, backward, left, right, and upward directions were assigned to each side of the figure, representing Jupiter, Mercury, Mars, Saturn, and Venus for the upward, which was believed to represent the appearance of the mother goddess, Ishtar. The idea of the Gobosei representing five planets was also seen in later Europe.
Further, each point was assigned to each of the five elements, which are the four elements of Fire, Water, Wind, and Earth and Ether (theology) added. It is used for the symbolism of magic, etc. even today.