The German states allied to Austria, except for Saxony, play little role in the main campaign of the war, which occurs in Bohemia.

Prussian Chief of the General Staff Helmuth von Moltke, having planned meticulously for the war, has rapidly mobilized the Prussian army and advances across the border into Saxony and Bohemia, where the Austrian army is concentrating for an invasion of Silesia.

In the the first engagement in the opening days of the Königgratz campaign, fought in Bohemia on June 26, 1866, Austrian commander Leopold Gondrecourt orders his troops—a battalion of Slovakian jäger and a battalion Hungarian line infantry—to attack the Prussian outposts at Hühnerwasser and throw them back across the Iser.

The attacking troops stumble across a Prussian company stationed between the trees, which alarms the rest of the Prussian force.

The four Prussian companies use the advantage of the Dreyse needle gun to stop Austrian attacks.

Gondrecourt now recalls his troops and retreats to Münchengratz, having lost two hundred and seventy-seven men.

Prussian losses are fifty men.