Tankaiko told this ama that the reason why he came to this place was because he needed to find a treasure called "Menko huhai no tama" (a gem that is beautiful from any angle), given by Emperor Gaozong of the Tang Dynasty, which was lost on the way to Kofuku-ji Temple in Shido Bay during a storm.
淡海公は海女にこの地にきた目的は、唐の高宗から下賜された宝物『面向不背の珠（めんこうふはいのたま）』を興福寺に届けるときに志度湾沖で嵐にあい紛失し、それを探しだすことだと語る。