And yes this picture is relevant.  Keep reading.

In the gaming world, there are many mechanics which can mean the  difference between Life and Death! Fun and Boring! Exciting and Dreary!

When to discard cards (down to the hand limit) isn’t one of them.

Or is it?

Concrete Example: CO-OP

In the current version of my game CO-OP: the co-op game, the question of when  to discard cards has moved through four (count ’em, four!) different  iterations of “When do players discard down to the hand limit?”

You might wonder: “Um what? Are there even that many places in the game you can discard?”  In the order that we play-tested and tried it out:

1) Each player discards at the end of his turn.
2) All players discard only after everyone has played, at the end of the Players Turn phase.
3) Players never discard.
4) All players discard only at the start of End of Day Maintenance phase.

Stage One:The Original

In the original version, each player discards down to the hand limit at the end of his turn. This means: Player 1 plays, then discards. Player 2 plays, then discards. And so on.

This led to some “questioning” of what happens if someone plays a card that give you more cards after you discard. For example, a player can play a card that allows everyone to draw another card. This led to players asking: “Do you have to discard again?” The answer: no: you only discard only at the end of the your turn, so you can potentially have a larger hand size.  It was definitely to the players’s advantage.

To try to “clear-up” the question above, there was a clarification in the rulebook to this effect.

Stage Two: Simpler Rule

One playtest noted that this rule would be a lot simpler to state if you just make everyone discard after everyone has played. That way, you don’t need any disambiguating FAQ in the rulebook for the nuance listed above.  Everyone just discards at the end of the turn after EVERYONE has played: no weird “over hand limit” rules. Everyone will ALWAYS be under the hand limit because everyone discards at the same time.

This seemed simpler to explain and avoided a corner case: so I changed it, simplified the rulebook (didn’t need the clarifying text anymore) and moved on.

Stage Three: No Hand Limit

One way to avoid the discard rule is simply to have NO HAND LIMIT: You don’t have to discard!

That’s as simple as can be. And, ideally that makes sense in a co-operative game: there’s no notion of balancing players. The game has a cap on how many turns are played, so you can’t play all your cards anyways. So even if you get a bunch of cards, it won’t throw the game off.

Boy, were we wrong.

A playtest just got rid of the hand limit and it was a disaster. Too much choice, too much maintenance, too much reading (as players had to read all their new cards), too much decision when it came time to play (as decisions opened up when you could have more cards).

At least for CO-OP: having a hand limit is important to keep the game tractable and (more important) fun. There was just too much choice with too many cards (see my blog post on this from earlier).

Stage Four: Discarding is Maintenance

So, CO-OP reverted to Stage Two mechanics: everyone discards after everyone has played.

A later playetest (with Stage Two in effect) noted that discarding is a maintenance rule. And they were right. The next phase after the players play is called End of Day Maintenance, so why not move the action to the start of the next phase?

Honestly, it makes perfect sense! Whether you all discard at the end of the player’s turns or the start of the next (maintenance) phase, it is operationally the same.

And conceptually, it’s easy to explain: discarding is a maintenance activity, so it should happen in a maintenance phase.

Annoying

Later on, I was doing a bunch of playtests by myself (exploring how  to make certain powers a little better). And, I kept getting forgetting to discard. It was annoying. Why?

I’d play my turn. My natural inclinatation was to discard at the end of my turn. But, I’d have to tell myself: “No, discard in the maintenance phase”. So, after everyone played, I’d have to go through and “refresh” my brain as to what my cards were were. Wasn’t I just looking at my cards when I played?

Caching

There’s a fundamental principle in Computer Science/Architecture for speeding up computation: it’s called “caching”. Caching is when you compute something computationally complex and  store in very fast (but very small) memory so it’s easy to recall again. If you use the same value again very soon, you can simply retrieve it quickly without having to recompute it; the result is a speedup.  For example: a Fast Fourier Transform (FFT) uses something called a “Twiddle Table” to store sin/cos of certain values.
Both sin/cos are fairly expensive things to compute (they are based on infinite series which is usually computed with a table lookup and an interpolation. Seriously, fairly expensive), but if you compute the same size FFT over and over again, you can “cache” these commonly used values so you don’t have to recompute them.
The problem with caching is that if you don’t use the  value you “cached” soon, it “flushes” and is no longer available for fast retrieval. Sometimes you don’t have enough space to “cache” everything you want, and the value you wanted gets flushed.  For FFTs, if your twiddle table gets too  large (for megapoint FFTs), your cached values can get flushed and you don’t get the speedup you hoped for.

Caching and Cards

What do FFTs and caches have to do with “When do I discard?” It’s all about what’s in the player’s brain (I.e., what has the player thought about recently so it’s in his “cache?”)

When I discard at the end of my turn, I have just played, so I am thinking about what cards are in my hand. The cards are “cached” in my brain.  It’s easy to think about.

When I discard AFTER everyone has played, I have flushed my cache. I have helped someone else, I have been looking at some rules, I  have been looking at somebody else’s cards. So, to discard,  I have to go look at all my cards AGAIN and decide what to discard.

The conclusion:  It’s more natural for a player to discard at the end of his turn when he is  thinking about his cards.

Full Circle

After all that, we came back full circle to the original rule! Each player discards at the end of his turn!

What about the “possible confusion” where players can have more than the hand limit? Well, it turns out it doesn’t happen that often. It’s not a corner case that comes up all the time. It’s actually fairly rare! If it does come up, a sophisticated group will realize that it’s a good thing, as someone can hold an extra card! A less sophisticated group might force down to the hand limit regardless, but it’s not a big deal. If it makes their life simpler, great. The group decides, which is the fundamental rule of CO-OP anyways: if there’s every a discrepancy, the group decides.

A strict rules lawyer will note that the the hand limit is ONLY enforced at the end of a player’s turn. This is a nuance that enables a few more opportunities in the game.

After all this, we can say with conviction this is the right thing: Each player discards at the end of his turn. It’s simple and natural, and tends to move play along faster (as the
card selection tends to be cached at that point). This rule has a small nuance to it, but once the players really understand this nuance, they will realize it’s good for them.