Because it is his Majesty the Lord makes his throne, the grand ceremony rachaphisek rachi is rated at 9, it's considered excellent Chakri dynasty May 5 each year, is a sacred harmony.
It is the day that His Majesty the King's coronation ceremony, the Queen ascended the throne as the ninth Chakri dynasty is considered the 5th day of May each year is auspicious.
Because the day the king hath the queen coronation came up to the throne was ranked 9 of the Chakri Dynasty is considered the 5 May of every year is the auspicious time.