There's also an issue with cards that say "if your opponent reveals x do this" (x being rock/paper/scissors)
Ok I came up with a makeshift way without using a third party.
>Both players set the top card of deck as the shield and peek at it. >Then they decide 3 numbers each, assigning Rock, Paper, Scissors to these 3 numbers. >The cost of the card in the shield must be assigned as the move that the player wants to use. The other 2 numbers can be anything. >Then both players reveal the set shield(Just drag it to grave). >The move chosen is the move assigned to the shield's cost. >After that the shield can be put at the bottom of the deck. Deck may be shuffled if nothing's been arranged.
A working example:
Player A summons Scissorspan, JK Sergeant. Both players set top card as shield and peek at it.(May use bottom card if top card is known to the other player or has been manipulated)
Let's say A gets a Pyrofighter Magnus as shield. He knows the cost is 3. He wants to go with paper. So he says, 2=Rock, 3=Paper, 5=Scissors.
B's shield is Jenny. Cost 4. He wants scissors. So he says 5=Rock, 1=Paper, 4=Scissors. (Remember that the same number may hold a different meaning for each player, like 5 here)
After this both reveal. A's shield costs 3, so it's Paper, and B's is 4, which is Scissors.
A=Paper, B=Scissors so B wins. A doesn't get to use the speed attacker effect, and as B didn't reveal rock, A doesn't get to use Scissorspan's second effect either.
Then the two cards are dragged to the bottom of the respective decks. Additionally, players may shuffle if the deck hasn't been manipulated in any way before(or if the last manipulation was a shuffle).