I believe that this door says, "Danger!" or "Caution!" in Japanese. Please correct any errors. The danger the door warns against is a shock from trying to open it without solving the magic square. Magic squares are probably old hat in dungeon tricks by now, but things like this fascinate me. I believe this was a classic 3x3 Lo Shu square where all the sums should equal 15. Set the dials correctly and the door is unlocked.