Don Brenneis sent this map on silk. He got it from a friend whose father was a career Navy pilot and had flown in the South Pacific. This was part of the survival kit for flyers who could be shot down and it shows winds and currents.

Side one shows the Western Caroline Islands and side two shows Palau Island Area and N.W. New Guinea.

FOTI is working on a better reproduction.

Fold out map from Nanyo Kohatsu Kabushiki Gaisya 20 Syunen (20th Anniversary of Nanyo Kohatsu Corporation), Nanyo Kohatsu Corporation, Tokyo 1941.   Larger Version
You can find Tobi by following the wide white border of the League of Nations Mandate to the island just before its Southwestern Point. The box with arrow on the left of that island contains no information except that company operations occur there. To the right of that island are the characters for Togobei Hatohobei in Japanese. The map shows shipping lines.  Photograph taken by Peter W. Black at Belau National Museum, Koror, 2006.

Relative Size Comparison of Babeldaob & Helen Reef
Palau Bureau of Lands and Surveys.

USGS Coastal & Marine Geology Program, Map of the Philippine Sea, Palau, & Tobi. Steve Tripp alerted us to this map, too.

A Navy map showing Tobi & Helen & a reef but not where Transit Reef should be. . . .
Steve Tripp sent this map.
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North Pacific Ocean, J.W. Norie & Co., London 1821, National Library of Australia. Once you zoom in, you can see Lord North's Island (Tobi) and Helen, called The Helen's Shoal & Reef. The NLA has the map in an interactive mode so you can zoom in and out where you like.

The catalogue entry is here.