How would you test a move whose cost is permanently revealing a piece's identity?

[u/Q-Gambit]

I'm developing Q-Gambit, a chess variant, and would like advice on evaluating a particular trade-off in its rules.

A piece starts with several possible identities. It can use a move allowed by a remaining identity; making that move eliminates identities that cannot make it. Both players can inspect the remaining candidates.

A concrete example from a CPU match: e2-f4 immediately leaves only Knight. The jump gets the piece out over the starting ranks, but it also gives up every non-knight move for the rest of its life. In contrast, a clear diagonal move can preserve Bishop and Queen as possibilities. Each side has exactly two original knight identities, so committing one also uses part of that shared quota.

The potential cost has two parts: reduced future mobility and information given to the opponent. I don't have human playtest data establishing that the knight jump is too weak. I'd like to distinguish players avoiding it because they misunderstand the commitment from players understanding it and finding it seldom worthwhile.

What would you look for in a small playtest to separate those explanations? Is there a useful comparison between positions or rule variants that isolates the commitment cost without changing several things at once? Examples of other games that spend future flexibility for an immediate move would also help.

Game context: https://q-gambit.com/ (guest tutorial and CPU practice; first guest entry has a terms/privacy confirmation). AI assists the coding and this post's English wording.

[u/Polyxeno]

Well an identified vs. an unidentified piece might be something you could estimate a value for using your own programmed opponent.

Intuitively, my guess is maybe it is worth a weghted (by odds it is each type) average of the values of all the pieces it might be?

[u/Q-Gambit → u/Polyxeno]

Thanks, comparing continuations with a programmed opponent could provide a useful baseline. One relevant rule: identities aren't secretly fixed and then revealed by a probability roll. Choosing a move removes incompatible candidates; the side's fixed piece quotas can narrow other pieces too. Both players see the remaining candidates.

So a weighted average would be a valuation hypothesis. It would also need to account for the value of keeping several kinds of move available, and how committing one piece affects the others. The weights wouldn't be odds of uncovering a hidden answer.

A comparison of matched positions would still depend on how the bot values that flexibility. Alongside it, asking human players to explain which options a move gives up could help separate misunderstanding from an informed decision to avoid it.

AI helped with the English wording.

[u/Polyxeno → u/Q-Gambit]

As a human player, I would be thinking of having a response for the potential moves of the unidentified pieces. But I would tend to take into account how likely each possibiliity is, too.

I would also consider exposing some pieces where they would reveal the pieces I was concerned about (and making threats the evasion of which could reveal type), and consider it an advantage to identify pieces, especially the stronger ones.

[u/Q-Gambit → u/Polyxeno]

The threat-and-evasion example is useful: a threat can be worth something even without a capture if the reply narrows an opponent's options. Which reply they're likely to choose matters as well as which replies are possible.

That suggests a focused playtest question: what response did you expect, which candidates disappeared, and did that change your next move? Watching those choices could help show whether players deliberately trade flexibility for useful information. Thanks for spelling out how you'd approach it.

AI helped with the English wording.

[u/Polyxeno → u/Q-Gambit]

Glad to have been of help. Sounds like an interesting project.

[u/zer0_state]

Two cheap tests. First, split comprehension from valuation by asking before the move, not after: have the tester say what they think the piece can still do after the jump. If they get it wrong, that's a comprehension problem. If they get it right and still decline, that's valuation. Second, to isolate the cost without changing anything else, set up the same position twice, once with the knight jump forced for one side and once with it forbidden, and compare results over a handful of games. If the side that jumped does no worse, the commitment isn't costing as much as it looks. Stratego's reveal-on-attack is the closest analogue I can think of for spending hidden information to get tempo.

[u/Q-Gambit → u/zer0_state]

Asking before the move is a useful distinction: an answer afterward could just reflect what the interface has revealed.

The forced-versus-forbidden comparison could flag interesting positions. Forcing the jump also removes the player's preferred alternative, so an unrestricted-choice condition could help show what that alternative was. Swapping sides and varying the order would help separate player strength and learning effects. A handful of games could guide further testing, but wouldn't establish balance on its own.

AI helped with the English wording.

[u/zer0_state → u/Q-Gambit]

Agreed that asking before the move matters; an answer given after the reveal mostly measures what the interface just told them. Your point about the forced condition also removing the player's preferred alternative is a good one, since the unrestricted-choice baseline is what would show what they gave up. Swapping sides and varying the order should help separate strength from learning effects. Small samples would only flag positions worth a closer look, as you say, not settle balance.

[u/Murelious]

Interesting idea. You'll probably find this interesting: Cloaks Gambit

[u/crashintuit]

Have you read this paper? Assessing Game Balance with AlphaZero: Exploring Alternative Rule Sets in Chess

[u/Q-Gambit → u/crashintuit]

Thanks for the reference. The paper's comparisons of first-move advantage, draw rates and use of special moves are relevant here: https://arxiv.org/abs/2009.04374

They suggest concrete measures for comparing rule variants. Whether a new player understands the options a move removes needs a separate comprehension check; strong self-play results alone wouldn't answer that. Q-Gambit's existing CPU hasn't established either result.

AI helped with the English wording.

[u/PhilippTheProgrammer]

The problem I see here is that with standard chess pieces there are going to be few situations where the identity of a piece will be kept ambiguous much longer than its first move. The only pairs of pieces that can perform the same moves are queen/rook and queen/bishop. But except for a few edge cases, you would want those pieces to be queens.

[u/Q-Gambit → u/PhilippTheProgrammer]

The shared quota matters here: each side has only one original Queen identity. Once one piece becomes Queen, another piece whose candidates are only Rook/Queen becomes Rook without moving.

Your concern about how quickly ambiguity disappears is still worth testing. Tracking how long pieces stay unresolved, and whether keeping those options changes a player's decisions, would tell more about that than win rate alone. I don't yet have human playtest evidence showing that this trade-off stays interesting.

AI helped with the English wording.

[u/PersonOfInterest007]

Playtests are always key.

Just one other thought: if you don’t lock in a piece’s identity until it has made two moves, there are far more possibilities. Or perhaps you have some initial small number of points that you can use to keep a piece’s identity unlocked until the next move, so that you can get one initial knight move out of a piece and then decide to spend a point to keep the possibility that it could end up as a bishop or queen.

[u/Q-Gambit → u/PersonOfInterest007]

Thanks, those suggest two different comparisons. Delaying commitment for every piece could test whether it happens too early; a small point budget adds a choice about which piece is worth keeping flexible.

One rule detail matters: would the first move still constrain the eventual identity? If it does, a knight jump still rules out bishop or queen, even if resolution waits. Letting it remain a bishop/queen candidate would instead be a temporary movement exception, which also needs a clear interaction with the shared piece counts.

Testing those versions separately against the current rules could show whether players use the extra flexibility deliberately, rather than simply making uncertainty last longer.

AI helped with the English wording.

[u/PersonOfInterest007 → u/Q-Gambit]

Have fun with the testing! Just make sure you’ve got enough diagnostics in place to really measure player behavior. Probably just recording all timestamped moves of every game, along with which rule variation is being used, is enough information to analyze.