This game is so fun! It would have been useful when I was learning Japanese in high school. This is like a recap for me. Reminds me of the time when I was in high school. Good times.
The keyhole is somewhere in the Giant Tortoise's patterns. The tiles can be rotated so that they show different symbols... resembling certain symbols in a certain order on a certain hint card ;)
 "Shop Empire Underground"){kind=icon}
 "Kana Warrior / かなウォリアー"){kind=icon}
 "Papa's Cupcakeria"){kind=icon}
 "Ubooly & Friends"){kind=icon}
 "Celebrity IQ Quiz"){kind=icon}
The keyhole is somewhere in the Giant Tortoise's patterns. The tiles can be rotated so that they show different symbols... resembling certain symbols in a certain order on a certain hint card ;)