Pias

Many thanks to nekoneko, who provided the screenshots and the riddles answers. Some explanations on these riddles:

Files A1-A4 are the answers of the riddles. Actually the answers shoudn't be showed before playing it. But some of the riddles require the knowledges about a local area of Japan, the dialect of it, and a nursery song concerns the area (with the lyric in the dialect). Therefore just having language skill isn't enough to answer the riddles for foreigners. Other riddles require the knowledge of variation how to pronounce or script Japanese. These also are difficult to answer for foreigners.