I tried to elucidate the prodcution date and the equivalent era name of the Seven-branched Sword (K. Chiljido) with the issue of an auspicious sign theory. In particular, it was confirmed that the era name indicated in the inscription engraved on Chiljido as ‘Bong-won (Ch. 奉元),' and that this sword was produced on November 16, the 4th year of King Jeonji's reign (408). In addition, the meaning of '丙午 正陽' and '奇生' among the main issues related to the inscription was examined. Through this process, it was figured that Chiljido was produced on the winter solstice day when the energy of Yang (Ch. 陽) was generated based on the principle of ‘奇生' from the Book of Changes. Therefore, it analyzed the meaning of 'giving it to a feudal lord(Ch. 冝供供侯 王) ' or 'the crown prince of Paekche issued an edict to make the sword for the king of Japan, so give it to future generations.' The meaning seems to reflect that the robustness of trigrams of the sky (Ch. 乾) and water (Ch. 坎) in the trigrams from the Book of Changes is Paekche, and the meekness of trigrams of the earth (Ch. 乾) and fire (Ch. 离) refers to Japan. Furthermore, given that ‘seven branches (Ch. 七支)' included in the phrase ‘Seven-branched Sword of 100 times tempered iron (Ch. 百練銕七支刀)' describes the characteristics of ‘the Jewell of Elephant' among the Seven Treasures of Chakravarti of Buddhism, the possibility of projecting the ideology of Chakravarti in the production of Chiljido was assumed.