Forging is a key part of the game, but you can do more than just create new pieces of equipment from scratch via materials. You can actually rework existing pieces of equipment to improve their quality, but these require Perfectionist Pearls. You can obtain these via crafting new items, but you will also be able to purchase them once you reach the Medal Academy, where they cost 100G each. The minigame is the exact same, so there is nothing new there, but you are able to get a piece of equipment from +1 to +3 via reworking. As long as you don’t fail, you will make progress towards this trophy/achievement, with it unlocking once you’ve successfully reworked 10 items.