structural:expansion, information:extraction
Foreign policies

One of the secrets of Bismarck's success was his careful in-depth study of the national interest of all the other states. He thereby avoided the pitfall of misunderstandings that led to conflicts. Even more important he identified opportunities whereby the national interest of another state was congruent to that of Germany, and a deal could be achieved to the benefit of both.

Summarizing Bismarck's mastery of diplomacy, Jonathan Steinberg argues:

The powerful Imperial German Army was under the control of Bismarck's close ally Field Marshall Helmuth von Moltke the Elder. It was a model of professionalism although it fought no wars. The Imperial German Navy was small under Bismarck.

After fifteen years of warfare in the Crimea, Germany and France, Europe began a period of peace in 1871. With the founding of the German Empire in 1871, Bismarck emerged as a decisive figure in European history from 1871 to 1890. He retained control over Prussia and as well as the foreign and domestic policies of the new German Empire. Bismarck had built his reputation as a war-maker but changed overnight into a peacemaker. In this role, he employed balance of power diplomacy to maintain Germany's position in a Europe which, despite many disputes and war scares, remained at peace. For historian Eric Hobsbawm, it was Bismarck who "remained undisputed world champion at the game of multilateral diplomatic chess for almost twenty years after 1871, devoted himself exclusively, and successfully, to maintaining peace between the powers". Historian Paul Knaplund concludes:

Bismarck's main mistake was giving in to the Army and to intense public demand in Germany for acquisition of the border provinces of Alsace and Lorraine, thereby turning France into a permanent, deeply-committed enemy (see French–German enmity). Theodore Zeldin says, "Revenge and the recovery of Alsace-Lorraine became a principal object of French policy for the next forty years. That Germany was France's enemy became the basic fact of international relations." Bismarck's solution was to make France a pariah nation, encouraging royalty to ridicule its new republican status, and building complex alliances with the other major powers – Austria-Hungary, Russia, and Britain – to keep France isolated diplomatically. A key element was the League of the Three Emperors, in which Bismarck brought together rulers in Berlin, Vienna and St. Petersburg to guarantee each other's security, while blocking out France; it lasted 1881–1887.