Still nosing around - not found anything relevant to the Japanese octopus myths was looking for but I did find:
http://www.lit.org/view/6955
http://www.jeremyrizza.com/twofist.guide.html
Emps
The Samoans believed that the forming of the ocean was the breaking of the ink sac of the primeval octopus. Another legend is that was a bit of salt water stored in small earthenware jar, but when it was lifted the water flowed out and caused a flood.
http://www.lit.org/view/6955
KANALOA ("Pinched Penny," middle right panel of page 11) is a Hawaiian god who in some myths is lord of fishermen and the sea, and in other myths, a magic-teaching octopus-formed god of the underworld. Still other myths hold him to be one of the creators of the world. The breakdown of his name, KA-NA-LOA, means "the great peace."
http://www.jeremyrizza.com/twofist.guide.html
Emps