System for secretly choosing between two options?

Question

I have a graphics project for school and the task is to design a board game. I need to work out a system by which two players can simultaneously make a secret choice between two options and then present their choice at the same time. I have thought about making a little arrow that can be spun around and then moved by the player to the choice they want to pick, hidden behind a screen, but it just feels a bit messy. And using cards that can be placed down seems to be a flawed system because as soon as one card becomes scratched and identifiable the whole game becomes unplayable.

I would really appreciate any suggestions you may have as to how to do this.

Answer 1

Each player puts a coin on the table under their hand. This will work perfectly if it's always the same two options, or if you can easily determine a sensible mapping from head/tails to the available two options.

Answer 2

When trying to make something new, it is not a bad idea to see what award winning games have already done.

You may wish to see the game Dixit (Spiel Des Jahres 2010) which has a simple system to let 2 to 4 players simultaneously choose between 3 and 5 options. The 2 option variant is Oltarus's method. Dixit also has wonderful artwork.

The expansion Dixit Odyssey solves the similar problem for 3-12 players. Its method is fairly similar to xorsyst's method. The choice is indicated by placing a peg in a hole. The peg is too stiff to be altered while under the hand, and so one is sure the commitment has been made while the player is covering the pegs with his hand. I would not suggest using the coin method with magicians.

Similarly, Apples to Apples requires players to simultaneously commit to an adjective. This is done by playing cards face down.

All of these games avoid the temptation of marked cards by having several reasonable quality cards. For instance, you can have 5 different "1st option" and 5 different "2nd option" cards, each with unique artwork. This allows more expressive play while also meaning a player can avoid a marked card if he actually suspects the other player is looking for such things.

In online games (irrelevant to your project, but possibly relevant to other readers), this problem is called a commitment scheme and is a very important cryptographic problem (that has been solved in several ways, some easy and some amazingly secure). The Yes/No variant is called bit-commitment or "virtual coin flipping".

Answer 3

If the choices are always the same (Always YES/NO, for example), the simpliest ways to do that are the following:

• Each players has two cards, one saying YES, the other one saying NO (Or whatever choice you have). They make choices by playing a card face down and revealing them all at once.
• Each player has a coin of some sort that can be placed in one's hand. YES is on one side and NO on the other (…). They make choices by puting it in their hand and opening them at once, the face up being their choice.

If the choices are always different (YES/NO sometimes, RED/BLUE or PINGUIN/ZEBRA sometimes), the best way is to have on your board a place for cards with numbers next to each place. (Fig 1.)

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Fig 1.

You must then have a deck of cards with propositions on them (YES, NO, BLUE, RED, …) and put one on each place. The players each have two cards or a coin, one card/face saying 1, the other one saying 2. Use the same technique as above.

NOTE: using cards, you can raise the number of possible choices.

Answer 4

The standard methods:

Cards - don't worry about scratches - many serious players sleeve cards these days. It's the most familiar choice. And if the cards are business card sized, they can be hidden in hand or under a hand on the table.

Spinners - not used all that often, however, the mold marks on the back of the spinner may be visible if using the commercial arrows; using a double disk the result can be inferred by watching the pre-choice state and counting the rotations.

I've "read" people's choices in both Dune (double disk) and in El Grande.

dice - also not used all that often, a die with the choices marked as symbols is quite viable; if the choice is reduced to numbers, it's also cheap. It's a bit fiddly, tho.

dreidle - since dreidles are essentially dice, the same issues apply, except that, having only one axis along which choices are made, it's easier to use.

Mat and screen - a mat with the choices marked, and a small marker to be placed upon that mat, with a movable screen - it's got the advantage of being easy to work, and very clear. It also provides a place for faction/side identification and/or cool art, as well as gameflow information.

Marker choice - player takes set of markers in hand, picks correct one I've used this in SFB for fire declarations. Cumbersome for many, due to half-inch square 1mm thick counters being the mode. Similar issues to cards, but since the counters could be hidden under the hand...

Answer 5

I'd recommend using a coin or a single card. They would both work the same - the player chooses a side and lays it on the table, facing up. Since there is only one card, you don't have to worry about them being recognizable by scratches. (Which, at its essence, is a mostly negligible problem.)

A similar system for multiple choices would be using a die. The player can place it on the table, his choice facing up. The advantage here is that with 4, 6, 10, ... options are readily available.

Edit: Oh, ok, I should have said how to keep them secret. I just assumed it could be done like the original question suggests - using some sort of a screen. Either one screen that separates the players, or even better, using an individual screen for each player. (Kind of like Revolution does it, see below.)

Image and commentary I wrote before I found out I'm not allowed to post an image: The Revolution! board game, showing screens for the red and yellow player.

If a die or a coin is used, covering it with one's hand may be enough, though.

Answer 6

I'd say that, by and large, the card method is what I'd choose, since I wouldn't be concerned about wear and tear on them. However, assuming that that remains a concern, you can expand beyond hiding a coin for a binary choice into using a bunch of color tokens (cubes, beads, what have you). Give each player a screen, with the choices explained on the back, and have them conceal the token in their hand to be revealed simultaneously. Note that this is basically equivalent to the card case, but the physical reproduction should be immune to concerns of wear and team - both due to the toughness of the materials and also due to the fact that they're completely concealed.

Answer 7

You can use a single card without a screen by having two orientations for it, like the "A" and "B" starting-city cards in 7 Wonders or the dual cards in American Megafauna. You play the card face down and then turn it over (being consistent about direction of turn!); whichever choice is "up" (toward the other player) is the one you chose.