Map of the North and Baltic Seas (labeledNord-See and Ostsee) from a folding postcard of five battlefronts: the Western and Eastern Fronts; North and Baltic Seas, Mediterranean and Black Seas; and the Serbian-Montenegro Front.
Karten sämtl. KriegsschauplätzeÖsterreichisch-serbisch-montenegrinisher Kriegsschauplatz.Deutsch - österreichisch - russischer Kriegsschauplatz.Deutsch - belgisch - französ. Kriegsschauplatz.Deutsch-englisch-russisch. Seekriegsschauplatz.Österreichisch - französisch-englischer Seekriegsschauplatz.Preis 20 HellerBei Änderungen der Kriegsschauplätze erscheint Nachtrag. Nachdruck verboten.Verlag Schöler, Wien-DöblingMaps all of theaters of warAustrian-Serbian-Montenegrin theater of war.German - Austrian - Russian theater of war.German - Belgian - French theater of war.English-German Russian - Sea theater of war.Austro - French-English - Sea theater of war.Price 20 HellerFor changes in the battle fronts, an addendum is shown. Reprinting prohibited.Publisher Schöler, Vienna-Döbling
"When the 1916 spring thaw began somewhat earlier than usual at the beginning of April, the Russians set to work renewing their minefields in the 'Central Position' and extending the minefields started in the 'Forward Position.' They also worked to secure their situation in the Gulf of Riga, renewing the fields in the Irben Strait and improving their Moon Sound position. The Russians began construction of the powerful 30.5-cm batteries at Zerel on the Sworbe Peninsula, dominating the Irben minefields, and at Cape Tachkona, on the northern tip of Dagö Island, commanding the southern flank of the advanced position."
All of the geographic references are to the Baltic Sea where Russia held its own against Germany. The Irben Strait is the primary channel to the Gulf of Riga; the Sworbe Peninsula is the southern tip of Saaremaa Island. These are (2016) parts of Latvia and Estonia. The 'Central' and 'Forward' Positions were defending the ports of Riga and Petrograd.
A Naval History of World War I by Paul G. Halpern, pp. 206, 207, copyright © 1994 by the United States Naval Institute, publisher: UCL Press, publication date: 1994
1916-04-06, 1916, April, Baltic, Baltic Sea
