Webcomic XKCD has soared to #1 on my list of comic favorites. Romance, sarcasm, math, and language? That’s pretty near all I care about. Warning: No inappropriate pictures, but a few have some language that might be considered NSFW.

Highlights include, but are not limited to, this one, this one, and this one. The last is very arguably NSFW. The first two are fine.

Today, a riddle.

I issue you and a partner the following challenge: I hand you five cards from an ordinary deck (no jokers). You stamp the numbers “1” “2” “3” and “4” on four of the cards, and hide the fifth. The choice of which to write on and which to hide is yours. You then leave the room and your partner enters. Given the four marked cards, your partner must guess the identity of the hidden card.

What strategy do you and your partner agree on beforehand that allows you to determine the hidden card? There is no need for trickery like imparting some meaning to the location of the mark on the card.

Warning: As it turns out, there is a lot of wiggle room in the solution. In fact, a solution exists even if the deck has 120 cards! Despite this, the riddle is strikingly hard. To my shame, I had to look up the answer, because after several hours, it was keeping me from getting any work done at the office. A mathematical background is not needed for the 52-card riddle, but it’s probably very useful if you try for 120.

Hint 0: A solution exists.

Hint 1: If you are like me, you will be tempted to throw away the ideas of suit and rank and just index the cards 0-51. While there is technically nothing wrong with this, starting with the cards divided into 4 groups is actually very natural and lends itself to an elegant solution.

Thanks to reader John Rhoadhouse for his help and thoughts in this and other riddles.

In other news: By popular demand, the return of 1KBWC next Sunday! If you are interested, let me know.

We got to play 1,000 Blank White Cards today! Turns out it was a lot of fun. For all those who missed it, we hope to have another game soon. You gotta come, people.
We had 8 players, none of whom had played before. The site linked says 3-6, but 8 was no problem at all. We also have some rules tweaks:

• There should be a “gentlemens’ agreement” that cards should not be played that prevent other people from playing the game or delay their turn for a long time. Examples include “skip a turn” or “reverse direction of play.” These might not be a problem in games with fewer people, but waiting fifteen turns to take your own is frustrating.
• Likewise, cards that require bookkeeping are discouraged. For instance, a card that says “All cards played after this one are worth +100 points” is a bad idea, because then you have to keep track of what cards are played later. A card that only modifies one card (like doubling its value or whatever) is fine because the cards can be stacked to note the effect.
• When all cards are drawn from the deck, players must immediately fill out all blank cards before proceeding further. This is to discourage creating huge, specific, game-swinging effects near the very end.

At the end everyone was allowed to choose three cards for the “Hall of Fame” of cards that would be brought to the next session. We also decided by acclimation to induct all defenestration-related cards.

The Hall of Fame:

As a cat, Lithium is unafraid of defenestration:

And a couple of the cards that didn’t make it to the Hall of Fame, but which were funny or influential:

Sorry about the lousy image quality. All I have is a digital camera. If I can rustle up access to a scanner, I’ll post better images of the cards.

Also, the cards I acquired are great, they look very nice and shuffle well, but they’re difficult to write on. Roller-ball pens smear, as do markers, and Bics have a tough time getting started. Sharpies work great but I didn’t have enough for everyone. This would be an advantage to ordinary index cards.
Everyone: Post your stories and take credit for your cards in the Comments!

So here are the good and bad points of Abridged:

The learning curve is much gentler. A good thing. Getting new people up to speed is much simpler. I think Bridge organizations are hoping Abridged brings new people into the game. I certainly hope it does as well.

It affords many opportunities to think about declarer play. Another good thing. Because you get to the play fast and usually end up in an appropriate contract, there is lots of practice declaring (and defending) hands. Because it’s easier to count face cards (knowing opponents’ point count), you can get practice at that too. Also, you get an idea of the kinds of hands that tend to take many, or few, tricks. I think this will shape bidding intuition.

The teamwork aspect is almost entirely gone. Kind of a lousy thing. The defense still plays as a team, but the feeling of connectedness with your partner is missing. However…

The opportunity for partner homicide is greatly diminished. I would feel comfortable playing Abridged partnered with a significant other, even a new player. As long as you don’t watch while they declare, you’ll never know even if something goes wrong. Go make a sandwich.

The opportunity for aggressive bidding is gone. Declaring in round one pre-emptively is a recipe for disaster. The contract is just too high. Down three is as good for your opponents as a slam. The power of low-to-moderate point, unbalanced hands is vastly reduced. As someone who enjoys bidding competitively, I missed this point a lot.

“Pffffft. Double!” is gone. Same thing. Nothing quite like the thrill of punishing your opponents for overextending themselves.

Most of the declarer knowledge gained by the bidding is still there. Part of declarer play is reading your opponents’ bids for hints as to the location of missing cards. Since you know their strength and length in their longest suits, most of this information is still available to you. In fact, declarer play is very similar, which is a good thing.

Slam bidding is gone. Yeah, it’s hard, and happens rarely so players don’t get a lot of practice. But bidding and making a slam feels like a real achievement in a Bridge game. In the practice games we played, I was dealt a 28-point monster (across from 4) and thanks to my knowledge of the opponents’ points, managed to take all the tricks. It didn’t feel the same.

3NT is gone. For the high bid, you’re in 4 of a suit or 4NT. Except in freakishly flat hands, you almost certainly want to be in 4 of a suit. The “ten” contract teaches the importance of 4-of-a-major bids, and I wish you got a bonus trick or something for declaring NT.

You can play pickup games without knowing each others’ conventions. This isn’t so much a skill level difference as a Bridge culture difference. I play Standard American and can adapt to the 2/1, but old American bidding systems with strong twos, 16-18 NT, and four-card-majors (as some older Bridge players play) are very strange to me. If I wanted to play a pickup game without taking 20 minutes with my partner to hash out our conventions, Abridged is the way to go.

The most interesting thing about Origins was the chance I had to play a new game called Abridged. It purports to be a simplification of Bridge—the same game minus the complex bidding. As a Bridge enthusiast I was interested but skeptical. After all, the bidding is a pretty integral part of the game.

First, let me mention that you don’t really need to buy the game to play it. The decks are ordinary decks of cards, except that the Jack through Ace have been changed to number cards (11-14) and the suits have been changed to colors. The rules are all online here, including the scoring, which I’ll gloss over. I actually got a free set—they were giving them away; I assume the ACBL or some other large Bridge organization was behind it. Seems like a smart move. There were about 40 people there to play Abridged and only 4 for Bridge, and I think a lot of people would agree that the game needs new blood badly.

So here’s how the “bidding” goes:

1) Starting with the dealer, every player gets the chance to preemptively contract to take 10 tricks. This is done without seeing partner’s hand. If you do this, the rewards for winning are larger, as are the penalties for being set. It’s kind of like pre-empting and being doubled.

2) Assuming nobody does this, all players announce the HCP count of their hand. Whatever team has the higher count is the declaring team, and the higher hand on that team is declarer.

3) Dummy lays his hand out (yes, before the opening lead. This is the one advantage the defense gets.) Declarer chooses whether to contract for 7 or 10 tricks, and also chooses a suit. Contracting for more tricks is worth more points.

4) All players announce the length of their longest suit; then the declarer’s left-hand opponent leads to the first trick.

The declarer has many advantages. He can always pick the right suit fit and can count tricks before deciding whether to go for 7 or 10. (Experienced Bridge players will almost never be in doubt.) You will never have the horror of looking at a completely unsuitable dummy, or realize that you missed a 9-card fit. Furthermore, knowing the opponents’ exact HCP count is a huge advantage because it allows him to locate specific cards much more easily. If your opponent had 6 points and has played an ace, you know that opponent doesn’t have the missing king. The defense’s advantage, and it’s bigger than it looks, is that the opening lead doesn’t have to be blind.

Thursday: An actual comparison/contrast of the play.

I spent a lot of time at Origins at the Playroom booth. I got to talk to the president of Playroom Games for quite a while about my games, and he accepted the prototypes. There’s still a lot of room in between the world as it is now and the world with my games published, but overcoming my fear of rejection and getting the games out there was a good step for me.

I also got to demo some of Playroom’s new games. Two were by Reiner Knizia. Knizia’s games have a very distinctive feel to them. The theme is secondary if not entirely incidental; the games tend very balanced between the players, with victory coming from making the very most of your resources, making careful sure to make the right move at the right time. The more compelling one was called King of the Beasts. There are 6 kinds of cards and a common pool of 5 available to both players. On your turn, you get to take all of the cards of any one kind; then you may take one kind of card and split them between the board and your private stash. The game is over once there are 6 animals of any one kind on the board, at which point you get points for having that kind of creature in your stash. So the key is finding the right balance between keeping the cards for yourself, to get points, and putting them on the board, so they’ll be worth anything at all.

I also saw, but didn’t have time to play, Killer Bunnies and the Quest for the Magic Carrot, which looks really good with a depth belied by its cute title. I’ll try to take a look at GenCon.

Next time I’ll talk about Bridge and “Abridged,” the simplification/variant that I got to play.