Nowadays Hwarang [花郎] is respected by the Korean as a symbol of Korean spirit. They say:
Silla developed its Hwarang (Flower of Youth Corps), a voluntary military organization. The Hwarang members were trained as a group in the arts of war, literary taste and community life, partly through pilgrimages. The educational objectives were:
1. loyalty to the monarch
2. filial piety to parents
3. amicability among friends
4. no retreat in war
5. aversion to unnecessary killing
These objectives were postulated by the famous monk Won-gwang, who consolidated Buddhist-Confucian virtues in the education of Silla youths. This movement became popular and the corps contributed to the strength of the Silla Kingdom.
Korea.net: History: The Three Kingdoms
Koreans believe it blindly, but it is no more than a fiction. Hwarang was not a training group of warriors, and the five disciplines they mentioned above, Sesok-ogye [世俗五戒], had nothing to do with Hwarang.
Hwarang [花郎] stands for "Flower Boy(s)." (Korea.net's translation is misleading.) It sounds sissy and fairy not only in English but also for people using Chinese characters. Why they were qualified as "flowery," although the Korean believe it was a group of elite warriors? It seems much more natural for a warrior to be qualified as "fierce" or "tough." Furthermore, when we liken men to flowers, we use another hwa (83EF) instead of hwa (82B1). Hwa (82B1) is usually used for women. So the name of Hwarang is closely associated with gay.
There are scarce historical data about Hwarang. No text written during Silla era survives. Main resources are three books: Samguk Sagi (1145), Haedong Goseungjeon (1215), and Samguk Yusa (1284). I recommend you to read these books in the original. (English translations are often inaccurate) You will be surprised how rarely Hwarang is mentioned.
Samguk Sagi, the oldest history book in Korea, consists of six parts: Silla Bon-gi (Annals of Silla), Goguryeo Bon-gi (Annals of Goguryeo), Baekje Bon-gi (Annals of Baekje), chronological table, Japji (miscellaneous records), and Yeoljeon (biographies). There is only an episode of Hwarang in Silla Bon-gi. It describes the origin of Hwarang briefly. The first term referred to Hwarang is "Wonhwa," and Hwarang was not male at first. The first members of Wonhwa were two women: Nammo and Junjeong. During the years of King Jinheung's reign, they were chosen by the king and soon had about 300 followers. But when Junjeong killed Nammo out of jealousy, Wonhwa was abolished.
Hereupon Samguk Sagi says that the king mustered young boys who looked good, made them wear makeup and decorated beautifully, and called them Hwarang. They were given freedom. Among them excellent persons were chosen and recommended to the court.
Samguk Yusa run the same story and it is more interesting. It says that after abolishing Wonhwa, the king ordered virtuous and superior boys from aristocratic families to be chosen and freshly made them Hwanang (not Hwarang). (*) Hwanang [花娘] stands for "Flower Girl(s)," although they were boys. What this means?
Samguk Sagi quotes Hwarang Segi by Kim Daemun, which says, "Bright ministers and loyal subjects are brought up here, and good generals and brave soldiers are born therefrom." It is clear that Hwarang in itself was not a warrior group. Although some Hwarang members later became good generals and brave soldiers, it is doubtful that they belonged to Hwarang when they rendered distinguished service.
When you read Yeoljeon (biographies) of Samguk Sagi, you will find it describe several Silla people joined Hwarang groups when young. But many of them had nothing to do with military affairs. Furthermore the relationship between each of them and the Hwarang groups is unclear. Although Samguk Sagi mentioned each of them became a Hwarang in youth, it tells nothing more. What did he do when he was a Hwarang? Till when was he a Hwarang member?
Hwarang is often mentioned in connection with Buddhism, which was severely suppressed during the Yi period. This was partly because the author of Samuguk Yusa was a Buddhist monk. Samguk Sagi and Samguk Yusa refer to Sesok-ogye [世俗五戒], which Koreans believe was the set of Hwarang's five disciplines during Silla. Ogye [五戒], the five precepts, are the minimal set of moral restrictions to be observed by Buddhist householder-practitioners. (*) Sesok-ogye was just a variant of Ogye. And according to Samguk Yusa, the famous Buddhist monk Won-gwang taught Sesok-ogye to Kwisan and Chuhang, who later joined the army and won martial glory, but nothing says that they were Hwarang members. (*) Sesok-ogye had nothing to do with Hwarang. "It was a set of norms for every day life of common people," said Prof. Shin Bok Ryong. (*)
Although Koreans do not want to refer to or just do not know it, Hwarang still existed after the collapse of Silla. According to Hunmong Jahoe (1527), the learner's dictionary of Chinese characters by Joe Sejin, Hwarang meant a male shaman during the Yi dynasty. At that time Hwarang were bottom in rank and disrespected.
Because of an inferiority complex toward Japan, South Korea needed something equal to Japanese samurai after the independence from Japan. So Koreans transformed mysterious Hwarang into brave warrior groups in the world of their imaginations. It was a convenient fiction for Koreans because Hwarang were prior to Japanese samurai. Some of them began to believe unquestioningly that samurai was influenced by Silla's Hwarang without foundation. Yes. By doing this they could beat hatred Japanese.