Here is the full list of all 17 Chess Knights: Viking Lands achievements worth 1,000 gamerscore.
Freed a prisoner held by a tower
Started the assault on Njord's Bay
Free a prisoner held by a bishop
Rescue the arrested from the docks
Start the assault on Midgard City
Free a prisoner held by a queen
Rescue the arrested from the village
Start the assault on Yggdrasil Way
Rescue the arrested from the forest
Start the assault on Ymir's Glaciers
Rescue the arrested from the glaciers
Rescue the last king from the Viking Lands
Save the lost ones from Njord's Bay
Save the lost ones from Midgard City
Save the lost ones from Yggdrasil Way
Save the lost ones from Ymir's Glaciers
Free every prisoner from the Viking Lands