Both players will then be shown a screen where they can decide how the duel will work. First of all each player decides which items they would like to risk in the duel. If you win the duel you get all the items the other player has offered, but if you lose then the other player gets your offered items. For instance you might decide that you will wager your ruby against your opponents sword. If you wish to just duel to see who is strongest there is no need to add any items.