Chess pieces are very valuable artifacts that are scattered on the whole world of Faeo. An evil and power-thirsty magician once locked the souls of the Yomas – beings that greeted the beginning of day and night on Faeo by singing – into them and covered every piece with a protective circle. When he realized that this made them stop singing he became very angry and brought them to the borders of the world. Nowadays, some of them have disappeared, others have been destroyed and some have been sold to the antiquarian. There even is a rumor that quite large amount of them were in the collection of King Magish.
There is a total of 15 sets of chess pieces, each of them consisting of a King, a Queen, two Rooks, two Bishops, two Knights and eight Pawns. When you help getting complete sets, so that the Yomas can sing again, you will receive a great reward. For sets of chess pieces you can receive armour pieces.
You can exchange the sets of chess pieces at Lady Dawn's Abode in
Lumirya Waterfall and at the Place of Shadows in the
Tomb of Kings.

Chess pieces can be found in instances in secret hiding places or as a monster drop – look at the Bestiary for the monsters that drop chess pieces.
You will receive the chess piece locked into an opaque oval case. In order to exchange your set of chess pieces you need to get each of them out of their case. You can do that by clicking on the "use" button.

This will open the following window:

When you are ready to take your chess piece out of the case to exchange it, click on “Confirm”. The chess piece will be taken out of the case and will now be in your backpack "naked". You will also receive the following chat message:

Note: When the chess piece has been removed from its case it will not be transferable anymore, so you will not be able to give it to other players or to sell it!