Japanese World War II Chart or Map of Hawaii, 1939

Depth soundings cover this sheet like a swarm of insects, thousands of tiny numbers marking how deep the Pacific runs between the Hawaiian Islands. The land itself gets far less attention. Oahu, Molokai, Lanai, Maui and the Big Island are sketched with thin contour lines and left mostly blank, while the water around them is crowded with measurements, current arrows and four large compass roses showing magnetic variation. For a sailor, the sea was the important part. This is a working nautical chart made by the Imperial Japanese Navy's Hydrographic Department in 1939, its Japanese title reading ハワイ諸島東部, the Eastern Part of the Hawaiian Islands.

The date matters. Japanese hydrographers were compiling and translating charts of Hawaiian waters two years before the attack on Pearl Harbor, largely by redrawing existing American and British surveys rather than sending their own ships. The word METRE appears in Latin letters at the top and bottom, a small clue that the source material had to be converted from fathoms. The grid of pale creases running across the paper shows it was folded down to pocket size and unfolded many times, and the browning is simply age and handling. Nobody designed this to be beautiful. Its appeal comes from the density of information and the strange fact that a document this dry sat at the edge of one of the twentieth century's turning points.