- In light of the Kaiser's decision to postpone the commencement of unrestricted submarine warfare, revised instructions are issued to U-boats today, intended to allow the navy to maintain an effective naval blockade of Britain without inflaming neutral opinion. U-boat captains are to draw a clear distinction between enemy and neutral ships prior to firing, but in making such distinctions more than the flag of the merchant is to be taken into account, including course, structure, and general behaviour of the vessel. Further, hospital ships are to spared, as well as ships belonging to the American-funded Belgian Relief Commission. Provided such precautions are taken, captains would not be held responsible if mistakes were made. The instructions bear the imprint of headquarters staff who have never had to determine the identity of a vessel through binoculars or a periscope while avoiding the threat of enemy fire. Expecting U-boat captains to make what essentially is a political decision whether to fire is to invite mistakes, which is precisely what will happen.
Even as the revised instructions go out to the submarine force, the German government gives a reply to the American note of the 10th objecting to unrestricted submarine warfare. On the one hand, the German government insists that they have the right to attack enemy ships as they see fit. On the other hand, they assure the American government that American ships will not be attacked, as long as they are recognizable as such.
- The southern advance of the German 10th Army today sees it pass between the Russian fortress at Grodno and the Augustow Forest. Here 10th Army takes up position facing both west and east, covering the escape routes from the Augustow Forest.
Of the Russian 10th Army, while III and XXVI Corps have made their way east and out of the forest, neither was aware that XX Corps remained behind them, and thus provided no aid to its withdrawal. Thus XX Corps finds itself today still in Augustow Forest, and that the German 10th Army has now cut the last avenues of escape.
- For the past few days, the Austro-Hungarian 3rd Army has been attempting to recover the key town of Mezölaborcz, and today the 21st Landwehr Division gains some ground near the village of Szuko. Otherwise, however, the strategic point remains in Russian hands.
- The French government decides today that the division assigned on the 4th to the Balkans is instead to be assigned to the Dardanelles operation.
- The merchant ship Rubens, disguised as a neutral Danish vessel to avoid interception by the British, slips out of Wilhelmshaven, beginning an unusual voyage. Its destination is German East Africa, and its assignment is to bring supplies to the German forces defending the colony, and in particular a load of coal to enable the light cruiser Königsberg to sail for home.