[AttakBanana]

I've enjoyed playing this.

The basic strategy that works for me:

1. If I have an obvious skew in the distribution of cards I've been dealt, I can assume the common suit and hence the goal suit and try to buy the cards of that suit.

2. If the distribution of cards I have is more or less even, then I just save that round and try to make back the base cost.

The hard part has been trying to understand how to update my beliefs based on the trades being made. If you assume everyone is making the rational choice, you might be able to come up with some strategy, but if its against humans who might be trying to bluff, I have no idea. Although, they say its a win-win game, so maybe theres a way there too.

[kccqzy]

Another way of playing is just simple buy low sell high without considering the goal suit. The reward for this style of playing isn't as high as correctly deducing the goal suit, but it's adequately successful. I think this is similar to market making: no matter how the market moves, the market maker makes a small amount of money regardless.

[AttakBanana]

Yup, that's what I mean by point #2.

[EvgeniyZh]

A better strategy would be to estimate card value based on your starting hand (i.e., probability that each suit is goal suit). It requires some non-trivial combinatorics but I guess if you take the game seriously you just memorize those once. Then you buy cards if the price are lower than your estimate and sell if it is higher. You also should pay a somewhat more for the card that gives you majority (4th/5th).

The updates are in this case, at least assuming others are doing something similar, is to increase expected price if you see sell for higher price and reduce if you see the sell for lower price. To figure out how much to update would be the hard part.

[AttakBanana]

Pretty much exactly what I meant.