The Mysterious Conches in Genshin Impact are special items found by the beaches of Kannazuka, used as bartering materials for a certain man’s chests. Collecting these items and turning them into the NPC Takashi will allow you to open a chest, which will lead to several special rewards.
To find the Mysterious Conches, you need to head to the Statue of the Seven in Kannazuka and head northwest. There will be a large building with the NPC Takashi standing inside, in front of three common chests. He’ll tell you he needs three Mysterious Conches per day, and he’ll let you open a chest in return.
Go to the beach in front of Takashi and look for shiny objects on the ground. You’ll dig up some items, and along the way, you’ll find Mysterious Conches. The locations of the Mysterious Conches are randomized in the area above, so you’ll have to search the whole area to find enough Conches.
You can only trade three mysterious conches to Takashi a day. In other words, you can only open a chest once per day. Once you open enough chests, you’ll get the Hamayumi blueprint, which is a free-to-play weapon that you can craft.
It’s an easy way to get a free weapon. Note, that you can do this quest on your own pace. You don’t have to return to the conches every day, so take your time.
