The Mixing Shop in game.
The Mixing Shop or Mix Shop is one of the many capsule shops located in the central shopping district near the fountain. The kanji 合(ごうgou) means "to join" or "to combine". The side of the building is labeled "MIX SHOP" and has a large "39" painted on the side.
Using the Mix Shop[]
The mix shop can be used to craft items and certain Super Souls. You can select "Mix from Materials" or "Mix from Recipe".
Choosing the "Mix from Recipe" will automatically show you what items you can create from the materials in your inventory, but there may be some recipes that it does not show you if you are lacking both materials.
Choosing "Mix From Materials" does not give any hints or recipes, you choose both items manually.