Phra Saeng Khan Chai Si[1][2] or Phra Saeng Khan Chai Sri[3] (Thai: พระแสงขรรค์ชัยศรี, the "Venerable Sword of Victory",[2] "Great Sword of Victory"[3][a]) is part of the royal regalia of the King of Thailand.
The sword’s neck between the blade and the hilt is decorated with a gold inlaid miniature of Vishnu riding the Garuda.
[citation needed] It is a double-edged iron sword with a quartz hilt, held in a scabbard made of gold, inlaid with precious stones.
[5] However, a story has been circulated that the sword was found in 1784 by a fisherman in Cambodia who found it in his fishing net (in Tonle Sap[citation needed]) at Siem Riep, and Chao Phraya Uthai Phubet who ruled presented it to Phutthayotfa Chulalok (Rama I) of Thailand,[6][c] his suzerain at the time.
The sword features heavily in the Oath of Allegiance Ceremony where the King ceremoniously dips the sword into a bowl of sacred water, and then drinks the water as an example, followed by senior civil servants and military officers as a sign of allegiance to the institution of the monarchy.