Instructions are in Japanese but just click on the big blue circle.
Here are the rules:
1. Only two people on the raft at a time.
2. The father cannot stay with any of the daughters without their mother's presence.
3. The mother cannot stay with any of the sons without their father's presence.
4. The thief cannot stay with any family member if the policeman is not there.
5. Only the father, the mother and the policeman know how to operate the raft.
6. Thief can stay on the beach, alone.
Brain exercise