The Polish army had 16,000 cavalry, a few thousand servants (who could and usually were used in battles), a few hundred infantry, plus 500 mercenaries and burghers from Gdańsk and 2,000 mercenaries hired by the Prussian Confederacy, all under the command of King Casimir IV, advised by chancellor Jan Koniecpolski and Piotr of Szczekociny.

They had not thought that their opponents could change their traditional strategy, or that the Teutonic soldiers besieged in Chojnice could be anything more than spectators.

The Polish cavalry charged, breaking the Teutonic lines, killing Duke Rudolf of Sagan and even capturing Bernhard von Zinnenberg.

Bernhard von Zinnenberg managed to release himself and organised the pursuit; hundreds of Poles, including Piotr of Szczekociny, were killed during the rout or drowned in nearby marshland.

The Polish King fought on with great personal courage and his knights had to force him to leave the battlefield.