The quality of Seiko is so high it was the official manufacturer of watches for Japanese soldiers during world war II. A small knob on each face will unscrew to open the sides of the clock face to unveil this.
Vintage Seiko Nautical Clock | Japan Double-Sided Electric Ship Wall Mount Piece
1917 w.h. willcox double sided print ! wood and iron ships blocks
18th Century Colifichet Embroidery On Paper Double Sided Neeedlework C 1790