Rhem 3 only allows 18 save slots.

When the Saved Slots were full, a copy was made to a "saveX"-directory, so that the 18 saves could be deleted safely, and one could start over again.

/Save1 directory starts the game, /Save3 evt ends it. Copy the contents - of one saveX-directory - to the ./DPOT directory (except maybe .DS_Store, pref.txt and vers.txt file).