A couple of weeks back I spent the weekend in Las Vegas. Despite almost 20 years of work in technology, this was my first trip to Vegas. A primary goal was to figure out if I could kill time in a casino without hemorrhaging too much money. Lots of friends — and fellow geeks — argued that Blackjack is the best way to conserve cash at a casino, turns out for that — for me — limit Texas Hold-em seems to fill that niche.

I don’t play much poker. I don’t play online and only occasionally join friends for games. I like playing poker, but for whatever reason the chance to play just doesn’t come up that often. Also, after an introduction to Ed Felten “teach your daughter to kick your butt at poker”-method in Singapore, I’ve been teaching my daughter how to play. But, to be clear, I am not a serious player by any stretch of the imagination.

So, I didn’t know what to expect. At the Mandalay Bay Casino, it turns out the cheap game is “3-6 Limit.” That is to say, Texas Hold ’em, but with $3 big blinds, $3 calls and raises until the turn when the minimum bet goes up to $6. Since it’s a limit game, there’s no all-in, pots stay relatively small, and fewer sharks are swimming around. Plus, the cheap tables are a goldmine of people watching.

After 3 days and probably 12-hours at the tables, I ended up about $450. Much of this came from hitting a straight-flush, which payed out a high hand bonus of $250, so really I was up more like $200. Still, given that I had a self-imposed limit of “lose no more than $200 over the course of the weekend”, this was a pretty good outcome.

Three quick takeaways:

• I’m glad I was playing low stakes, as at one point I was about $150 down. If I was playing higher stakes, I would have hit my limit and had to stop.
• I played too aggressively. Way too often I’d stay in with off suit queen seven, or similar. This is a good way to chase pots and lose money. Laying down crap is important.
• I rarely used early, aggressive betting to scare people out of hands

On the flight home, I got curious about how the numbers worked out. You can go online and look up the odds of various hands winning in Texas Hold ’em, but that isn’t any fun, so I wrote some code to simulate random games. My results matched what you look up online. With 7 players, starting with paired aces gives you about a 40% winning percentage, with a steady drop through the face cards to paired jacks’s giving you about 25%. Open ended straight-flush draws, say queen jack on suit, start a bit below that.

What surprised me a bit, however, was what happens if you are able to pare the field down a bit. If you assume a bunch of smart players — people generally laying down if they had neither a pair, two high face cards, or open straight flush, your odds rise pretty dramatically, about 20% across the board. For example, the high pairs move into 50-60% range of winning percentages. What this says is that while I played too aggressively, I didn’t use aggressive betting to narrow the field. Obviously, with low stakes limit, people will pay to stay in longer, but a bit of up front betting would have helped.

Anyway, it was a fun weekend and a nice excuse to play with Ruby, rspec, and Cucumber to do some modeling.