I’ll come right out with it: I’ve become obsessed with UNO on Xbox Live Arcade. I hadn’t played UNO in a long time. It’s an interesting game. Some poker skills actually transfer over nicely.

However, UNO is insanely random. Even more so than poker, someone who is “good” can often be beaten by someone who has almost no clue what they’re doing. That said, one should be able to increase their chances of winning any given four-player game to over 25%.

I should also point out that the games are a lot more fun once you’ve played a while and boosted your “TrueSkill” up into the 20s. Up until that point you run into a lot of, erm, morons. You’ll still run into morons, but at least these morons will typically stick through an entire match.

I titled this post “Part 1″ because I’m sure I’ll have more to say; not because I have some grand plan here. In this one, I’m going to concentrate on Wild Draw Four. This is some pretty common-sense stuff, but I wanted to write it all down. These are really just scattered notes.

Wild Draw Four is a pretty mean card. It forces the next player to draw four cards and they miss their turn. You’re only supposed to play it when you don’t have any card of the color that needs to be played. Note that I said color. If a green 4 is on the table and all you’ve got is a WD4 and a red 4, you can play the WD4 and win a challenge.

Anyway, if the victim challenges your WD4 and it turns out you were bluffing, you have to draw four cards and the victim doesn’t lose their turn. If you weren’t bluffing, they have to draw 6 cards instead of 4.

How can you tell if someone may be bluffing? It really depends, but generally, if they have a ton of cards in their hand and they play a WD4, they are likely bluffing. If they only have 4 or 5, they’re probably not. It’s also somewhat more likely that they’re bluffing it they’re playing it at a particularly convenient time, when you have UNO, for example. Careful with that one, though.

And if a player has 2 cards and plays a WD4, changing the color and leaving them with 1 card — don’t challenge it. I have no idea why people challenge in situations like that. They’re almost never bluffing, and have very little incentive to. The only time I can think of that this would make sense is if you played a wild card and called UNO, then it went around to the player who proceeds you without changing color, and that player has only a numbered card of that color and a WD4. In that or similar situations, it really would make sense for them to bluff — in fact, it’s the only reasonable thing to do.

But if you have a handful of cards and someone with 2 cards plays WD4 on you, they’re probably not bluffing. The only motivation they’d have to bluff is if they think they’re going out very soon and they want to fatten up other players’ hands. But if they’re close to winning, they’ll likely have few cards, which makes it less reasonable for them to bluff.

You won’t see this often in the 20+ TrueSkill range, but it does happen — The current color is (for example) red, and someone with a lot of cards plays a WD4 and chooses… red. I’ve seen this. Someone tried it on me. Of course I challenged it and won. If the current color is red and they play a WD4 and change it to red, that implies that they have red, and can thus be challenged. A few games later I saw someone do this to someone else and the other player didn’t challenge. I’m not sure why. Perhaps they assumed that the guy who played the WD4 was insane. At that point, even if the player is insane, you’re really better off challenging it.

As far as I can tell, most players don’t bluff with WD4 most of the time. The vast majority of challenges I see are lost. I think that most players like to hold onto WD4 for an appropriate time or something.

When should you bluff? WD4 is worth 50 points if it’s in your hand for another player when they go out. Sometimes you have to bluff, especially if you’re sure you’re about to lose. It doesn’t matter if they challenge you and win, since there’s a decent chance that the four cards you’d have to draw won’t be more than 50. You could draw three Reverses and you’re screwed, but hey. And if the player had UNO and didn’t challenge, then you might be ok for a while longer.

Finally, sometimes you can catch someone bluffing when they appear to being playing WD4 out of anger. If they recently were forced to draw a lot of cards and now have the chance to pay someone back, they’ll sometimes bluff a WD4.