On Sept. 2, 1945, an American Navy squadron came ashore at Sagami Bay near Yokohama to demilitarize the Japanese midget submarines in the area. They found this notice on the door of a marine biological research station there, left by embryologist Katsuma Dan.

The Americans honored his wish: On the last of 1945 he was summoned by an officer of the U.S. First Cavalry and handed a document releasing the station back to the University of Tokyo.

The notice is on display at the Woods Hole Oceanographic Institution’s Marine Biological Laboratory (here’s the full story).