No chess-game is played by Gawan in Parzival. However, there is a moment in the story where an imaginative use of chess-pieces comes into the story. Attacked at the Castle of Schanpfanzun, Gawan is helped by his love-interest, the Princess Antikonie:

The Princess ran this way and that in search of some weapon to use against the treacherous throng, till, at last, spotless maid, she found a set of chessmen and a board, huge and beautifully inlaid. This she brought Gawan to fight with. It was hung up by an iron ring, which Gawan gripped as he took it. On this square shield much chess had been played, but now it was badly hacked away.

Hear about the lady, too. The pieces were large and heavy. Yet king or rook, she hurled them at the enemy. And it is narrated that whoever was hit by her throws was toppled, despite himself. The puissant Princess acquitted herself there like a true knight, she was fighting at Gawan's side [....] In Schanpfanzun, Antikonie was made to know sorrow, and her pride was humbled. As she fought, she shed copious tears. But she gave clear proof that affection between lovers is steadfast. (210)

From Wolfram von Eschenbach's Parzival. Translated by A.T. Hatto