This extremely rare sea chart of the Singapore and Banka Straits was made by the Oberkommando der Marine (Nazi German Navy High Command) on the eve of the Japanese conquest of Malaya, Singapore and the Dutch East Indies (Indonesia), in late 1941 and early 1942. It was one of seminal navigational aids used by the commanders of the Monsun Gruppe (Monsoon Group), the special German U-boat force based in Japanese-occupied Southeast Asia. The Monsun submarines terrorized Allied shipping along the vital India-England routes, while transporting ultra-precious cargo between Germany and Japan. The present example of the chart has an important provenance, having been a ‘headquarters copy’ consulted by senior officers at the Wilhelmshaven Navy Yard, Germany’s leading U-boat base.
The chart extends from the southern tip of the Malay Peninsula and Singapore Island, and the southern end of the Malacca Strait, in the north, all the way south past the Riau Archipelago and along the east coast of Sumatra, down to the mouth of Banka Strait, which led towards Jakarta and the Sunda Strait. The chart covers one of the world’s key maritime transport nexuses, connecting the Indian Ocean with the Asia Pacific region.
The city of Singapore is clearly outlined, while the Federated Malay States Railway (FMSR) is shown to run northwards into the interior of the Malay Peninsula. The chart is an extremely advanced scientific work, with the coastlines precisely demarcated by trigonometrical surveys, and the seas marked with copious bathymetric soundings and the marking of reefs, other hazards and navigational markers (with some lighthouses and other aids heightened in yellow stencil).
The information showcased on the map is primarily taken from British and Dutch sources, but perhaps also includes some details supplied by the many German merchant vessels that plied these waters in peacetime. A curious, crudely printed recent addition to the chart is the marking of the ‘Verbotenes Gebiet’ (Prohibited Area), seemingly referring to a restricted military zone along the coast at the southeastern tip of the Malay Peninsula, to the east of Singapore.
While the text of the map is generally in German or transliterated into that language, many names of a variety of tongues are present. Accordingly, the chart features the ‘Bemerkungen’ (Remarks), in the upper-left corner, noting the ‘Fremdländische Wörter’ (Foreign Words), giving the equivalent nautical terms in English, Dutch, Malay and German.
The template for the present map was first issued by the Imperial German Navy in 1911, but was heavily revised and reissued by the new Nazi regime in 1935, while the note in lower left margin reads that the chart was updated with ‘Kleine Berichtigung’ (small corrections) on various given dates, with the most recent incorporated on the present chart added on ‘1941.11.IX.’ (September 11, 1941). The present char was printed shortly thereafter, and an inventory stamp in the lower margin the reads ‘1941, 31 XII’ (December 31, 1941), confirming that the chart was inventoried on that date. A purple stamp, in the lower left margin, reads: ‘Die Karte wird vom letzten kleinen Berichtigungsdatum ab bis auf weiteres nich mehr berichtigt’ (The map will not be corrected from the last minor correction date until further notice).
An Intriguing Provenance
The present example of the map possesses a very interesting and important provenance. Both near the title and on the verso of the chart are the stamps of the ‘Kriegsmarinewerft Wilhelmshaven Kartengruppe’, featuring the Nazi insignia. This means that the chart was entered into the map library of the Wilhelmshaven Naval Shipyard, Germany’s largest U-boat base. Thus, this chart was ‘headquarters copy’ that would have been consulted by senior naval officers while planning U-boats deployments.
In 1945, following the end of World War II, the Wilhelmshaven map library was moved and merged into the archive of the newly-formed Deutsches Hydrographisches Institut (German Hydrographical Institute), in Hamburg. The Institut was the successor of the Norddeutsche Seewarte (North German Naval Observatory), and henceforth became the main library of the West German Navy. The present chart features the handstamp of the Institut, near the title, as well as, in the bottom margin, an ‘Archiv D.H.I.’ handstamp over-stamped with the word ‘Erledigt’ (meaning ‘Deaccessioned’), and well another D.H.I. handstamp labelling chart as a ‘Doppel (Ausleiheexemplar)’, meaning ‘Duplicate’ and ‘Loan Copy’, also over-stamped with ‘Erledigt’. This mean that the present chart was a duplicate that was officially deaccessioned for the library. Indeed, following German reunification in 1990, the BHI was reorganized as the Bundesamt für Seeschifffahrt und Hydrographie (BSH, Federal Maritime and Hydrographic Agency of Germany), which had premises in both Hamburg and Rostock. The BSH decided to deaccession many (usually duplicate) items from its archives, including the present chart (from its Rostock library).
The pink handstamped box with the note ‘Siehe Nachr.[icht] für Seef’ (See Message for Safe) is a Nazi-era detail intended for any storage/security notes that map apply to the chart.
It is worth noting that most Nazi charts featured (often numerous) handstamps, a result of the Third Reich’s obsession with classification and order.
A Note on Rarity
All issues of sea charts published by the Nazi German Navy are very rare, being much more uncommon than comparable British or American charts. This had a great deal to do with the fact that the Nazis were far more secretive with their charts; they were considered ‘highly classified’ and were produced in only very small print runs for restricted use by senior naval officers. For instance, access to the ‘Kriegsmarinewerft Wilhelmshaven Kartengruppe’ library would have been tightly controlled. Moreover, most of the examples which did circulate would have been exposed to wear during headquarters strategy sessions or onboard vessels, leading to a very low survival rate.
We can trace only a single example of the present Nazi era edition of the chart in institutional holdings, held by the Bundesamt für Seeschifffahrt und Hydrographie at their Rostock premises (this is seemingly the sister copy of the present example, which is its ‘Duplicate’). Moreover, we cannot trace any sales records.
Interestingly, the U.S. Navy was well are of the chart during World War II, as the 1935 edition was citied in their 1944 Gazetteer of sources on Southeast Asia.
The ‘Monsun Gruppe’: U-Boat Warfare in the East
Throughout World War II, India, Ceylon, Australia and New Zealand were vital to the Allied effort, as they were the source of vast quantities of manpower and materials. For Britain, maintaining the shipping corridor through the Indian Ocean and around the Cape of Good Hope was of vital strategic importance.
In the early days of the war, Germany deployed merchant raiders and pocket battleships to the Indian Ocean and the South Atlantic to attack Allied shipping. This initially met with some success, but as the Axis powers did not yet control any harbours in these regions for the German submarines to refuel or shelter, the British East Indies Fleet eventually devised ways to pick them off or to drive them away. While the Oberkomando der Marine considered deploying U-boats to the Indian Ocean as early as December 1941, this was overruled as virtually the entire submarine fleet was preoccupied with the so-far highly successful prosecution of ‘Unrestricted submarine warfare’ in the North Atlantic.
On the morning of December 8, 1941 (local time), at the same moment as the Japanese raided Pearl Harbor, Japan attacked British possessions in East and Southeast Asia, in a stealth move, as Tokyo had not declared war upon London. Hong Kong was besieged and fell on Christmas Day, while the Japanese rolled over British Malaya. Following the Battle of Singapore (February 7-15, 1942), Britain surrendered its main base in Southeastern Asia, in what was one of the greatest disasters in British imperial history. Meanwhile, the Dutch government in exile, in charge of the Dutch East Indies (Indonesia), had declared war on Japan. Japan promptly invaded the archipelago, crushing the defenders and gaining the complete Dutch surrender on March 8, 1942. Japan now dominated Southeast Asia.
The Japanese occupation of Southeast Asia opened up a whole new realm of possibilities for Axis operations in the Indian and Western Pacific oceans. Specifically, German and Japanese submarines could now be deployed to attack Allied shipping in the Indian Ocean, if not crippling Albion’s link to India, Ceylon, Australia and New Zealand, or at the very least terrorizing the enemy, sapping their morale and forcing them to redirect scarce resources.
Moreover, Axis submarines could be used to facilitate technology transfer between Germany and Japan, as maintaining a physical link between the two allies was otherwise quite difficult.
Japan caused much distress the to the British in March and April, 1942, when their planes (launched form aircraft carriers) made daring raids upon the British naval bases at Colombo and Trincomalee, Ceylon, as well as attacking Allied shipping the Gulf of Bengal.
While Japan initiated the Axis deployment of submarines into the Indian Ocean-Asia Pacific, it was understood that the German U-boats would be far more effective operating in those theatres. While the Japanese submarines were effective for long distance voyages (some could travel as much as 10,000 before needing to refuel!) and delivering war supplies, the German submarines were faster and nimbler. Moreover, German crews also had far more experience with hunting enemy vessels.
In mid-1943, Grand Admiral Karl Dönitz authorized the formation of the Monsun Gruppe (the Monsoon Group), a special U-boat force that would be permanently based in Japanese-controlled Asia. While the summaries would be under German command and manned by German personnel, they would use Japanese harbours and resources, and would coordinate their operations closely with the Japanese naval command.
Commanded by Captain Wilhelm Dommers, the Monsun Gruppe had their main base at Penang (Malaysia), a secondary base in Kobe, Japan, while Singapore, Jakarta and Surabaya were designated as refueling stations. Notably, the present chart depicts a major zone of the force’s operations in the vicinity of one of their key way stations. Over the next year and a half, a total of 41 U-Boats (mostly of the Type IX model) were deployed from Germany to serve on the force.
The Monsun Gruppe succeeded in sinking a good number of Allied ships, including some large freighters laden with precious supplies. It also caused a sense of alarm amongst the command of the British East Indies Fleet, forcing the Allies to deploy far more aerial and marine resources to protect their conveys than would otherwise have been the case. The Monsun Gruppe also played vital role in Axis technology transfer, delivering blueprints and parts for aircraft, tanks and ships from Germany to Japan. In turn, the U-boats brought back precious raw materials from Southeast Asia (tin, rubber, etc.) to Germany.
However, the Monsun Gruppe was gradually won down by the immense challenges and dangers of its mandate. First, the great distances involved in patrolling the Indian and Western Pacific oceans, meant that the Monsun Gruppe’s resources were always strained. Moreover, the Allies increasingly found effective ways of detecting and neutralizing the U-boats, leading to the loss of many vessels.
By the end of 1944, the Monsun Gruppe was a greatly reduced force, and it was rolled up to become come part of the newly integrated Southeast Asia U-Boat command, which continued to aid the Axis cause until Germany’s final defeat in May 1945 (Japan would not capitulate until August of that year).
References: Bundesamt für Seeschifffahrt und Hydrographie (Rostock): R 424(1941)BSH.
Cf. (re: 1935 edition): HYDROGRAPHIC OFFICE, U.S. NAVY, Gazetteer (No. 10) Sumatra (Washington, D.C.: Government Printing Office, August 1944), p. 279; HYDROGRAPHIC OFFICE, U.S. NAVY, Gazetteer (No. 11) Malay States (Washington, D.C.: Government Printing Office, October 1944), p. 206; (re: the Monsun Gruppe:) Gordon WILLIAMSON, U-Boat Bases and Bunkers 1941–45 (London, 2012), p. 31.