A detailed close-up of a vintage leather diary with a heart-shaped lock and a key inserted, on a wooden desk with a quill pen.

Open the diary so the metal hasp (the little loop on the cover) is visible. Insert one key into the heart lock’s keyhole fully. Turn the key gently (usually about 90°) — you’ll feel the shackle or latch release. Remove the shackle (the U‑shaped bit) from the hasp so the diary can open, or push the hasp through and close the cover when you want it locked. To lock: close the diary so the hasp aligns with the lock, push the shackle into the lock until it clicks, then remove the key. The lock should stay shut. To unlock again: insert the key and turn it the same way — the shackle will release. Don’t force the key. If it’s stiff, wiggle gently while turning — forcing can break the key. Keep both keys safe. The set usually includes 2 keys — store one somewhere safe in case you lose the other. If the key is stuck: hold the lock steady, pull slightly outward on the key while turning gently. If you lose the keys: try to find the spare key first. If none, bring the lock (or diary) to a small locksmith or the store — they can open it or replace the lock without damaging the diary. Avoid wetting the lock — tiny metal locks can rust or get sticky if exposed to water. See more