These are some cheatcodes Nintendo offered for the game when it was released. They all give usefull itens. To use them go to the Sushi Sprite Shrine, after a certain poin in the game. They should all be typed in All Caps.

Effect	Password
3 Guardian Charms	SAM MONROE
Big Renewal Bean	SASHA IMI
Exp Charm L	SUE SHEEN
Searing Torch	ED AMAME
Skill Charm	DON BERRY