how to unlock the chest in arcane library
Open the chest by finding its matching hidden key first. In Librarian: Tidy Up the Arcane Library , each chest is unlocked by one of four keys scattered around the library, and several guides agree the keys are hidden in places like a chair/bench area, under the library logo, inside a vase, or on an upper shelf area.
What to do
- Search the nearby room carefully for interactable objects.
- Check common hiding spots: chairs, benches, vases, under signs/logos, and high shelves.
- Collect the key, then walk up to the matching chest and open it.
- If a chest seems inaccessible, unlock movement or jumping abilities first, since some keys are placed up high.
Chest rewards
The chests reportedly unlock permanent upgrades or abilities, including things like jumping, sprinting, carrying more books, or other minor magic improvements.
Quick tip
If you are stuck, the chest is usually not the hard part — the key hunt is. One video guide says the first chest can even be opened only after you get an early mobility upgrade that helps you reach later keys.
TL;DR
Find the hidden key for the chest, then use it on the matching chest; the keys are usually tucked into furniture, vases, signs, or high shelves.