Simplify the following text for a Grade 5 native English-speaking person.
Original: OtogizÅ shi refers to a group of approximately 350 Japanese prose narratives written primarily in the Muromachi period ( 1392 â `` 1573 ) .
Simplified: OtogizÅ shi are a group of short stories with pictures , written in Japan , mostly in the period between 1392 and 1573 . There are about 350 of these stories .