Item duplication is the duplication of a bottled item. There are 4 ways to do item duplication

  • ESS bottle duplication of recaptureable items. You catch a recaptureable item then use it to ESS dupe, which won't get rid of the bottled item then you recapture the released item. The only recaptureable items are a bug and a fish.
  • Release a bug, which will make 3 come out, then recapture 2 of them. If you're really fast, you can recapture all 3 bugs you released before they burrow under the ground.
  • Capture a renewable bottled item then leave the area and come back. It will be there again. It's not called item duplication unless it's gone as soon as you capture it so you can't dupe spring water. The only nonrenewable captureable items are zora eggs and the big poe soul in Ikana Graveyard. The big poe soul in the Ikana well is totally renewable. The Deku Princess will only be there again after you capture her then leave and come back if you capture her in a duped bottle.
  • Catch an item in a duped bottle not in a trade item slot that doesn't come back after you leave the area, play the song of time which won't remove it from the bottle, then catch it again. It will also come back after leaving the area and using the Song of Time Storage.