TATSU can mean Rise and Dragon in the Japanese language.  Sapphire is the gemstone for royalties.

A specially selected Ceylon Sapphire of 1ct or above in oval cut shall be used as the center stone of the TATSU Ring.   TATSU is designed with two Diamond halos, one of which immediately surrounds the Sapphire, the other, using larger Round Brilliant Diamonds, is separated by 8 symmetrical lines made from Gold.

The number “8” is considered an auspicious number and also derived from royalties in Japan.