In God of War Ragnarok, special equipment is required to unlock doors and navigate obstacles. The main story quest can be completed, or you can get it by hitting a particular checkpoint or milestone.
The Draupnir spear is one example of this. Although it can also be utilized as specialized equipment, it is the third core weapon.
The blue symbol doors are one of the obstacles you can run into, and we’ll show you how to open them.
God of War Ragnarok, How to Open Blue Symbol Doors
A blue symbol door can be unlocked with the same chisel you used to open Valkyrie doors in the first game. It will first require an enchantment, though. You will run into Freya when you first arrive in Vanaheim.
She will be your teammate and the one to enchant your chisel, enabling you to open these doors with blue symbols.
You can go back to the locations where you first saw these doors to unlock them after she has finished enchanting them.