The Se Sok O-Gye, sometimes also referred to as just O-Gye, is the moral code of the hwarang formulated by a Buddhist monk named Won Gwang (원광: 圓光) consisting of five rules:
- 사군이충(나라에 충성하고) - 事君以忠 - Loyalty to the king
- 사친이효(부모님께 효도하고) - 事親以孝 - Devotion to one's parents
- 교우이신(믿음으로 벗을 사귀고) - 交友以信 - Trust among friends
- 임전무퇴(싸움에 나가서는 물러서지 않으며) - 臨戰無退 - Never retreat in battle
- 살생유택(살아있는 것을 함부로 죽이지 않는다) - 殺生有擇 - Kill only with forethought
The code is still used by many Korean martial artists and can be found in gyms around the world.