Settlers of Catan is one of the most popular board games in the world. Those people who already played it a couple of times probably noticed that it's a very complex game which takes more skill than luck in order to win it. A player may not be able to influence his luck factor, but indeed he can influence his skill factor by thinking about and carefully executing a winning strategy. This task turns out to be a real challenge since every game is unique like a fingerprint.

One of the most crucial skills which proves to have the biggest impact on the end result of a Settlers of Catan game is the ability to make profitable deals/trades with other players. Thus, the more profitable deals you make, the more you tilt the odds of winning to your favor. While a basic strategy is about concentrating a player’s resource production to Ore/Grain or Lumber/Brick, an additional advanced strategy can be used to increase the number of profitable deals by a significant amount.

In order to achieve that goal, the following techniques can be used which do not violate the original Catan rules. To better illustrate those techniques, let us assume that we have a base game with 4 players Andrew, Bob, Charlie and Dan in this given turn order while considering 3 different game situations.

Harbor Commission Deal: It’s Andrew’s turn. He owns the Grain harbor and has 1 Ore in his hand. An average player in Andrew’s position is likely to just end his turn. A skilled player may instead ask if someone wants to use his Grain harbor for a commission. Bob has 2 Grain + 2 Lumber on his hand and accepts the deal. This should work as follows:

Step 1: Bob passes 2 Grain + 1 Lumber to Andrew and receives 1 Ore from Andrew. This counts as an ordinary trade.

Step 2: Bob requests a Brick and Andrew trades the 2 Grain with the bank for 1 Brick. 

Step 3: Andrew trades his 1 Brick to Bob and receives his 1 Ore back. This also counts as an ordinary trade.

Andrew ends up with 1 Ore + 1 Lumber in his hand. Bob ends up with 1 Brick + 1 Lumber and may build a road in his next turn. This effectively means that Bob used Andrew’s Grain harbor and gave him a commission (1 Lumber) for doing that. The commission itself is subject to negotiation, but most of the time Andrew should accept any resource since it is effectively for free from his point of view.

The Harbor Commission Deal is even more powerful in a 5-6 player game since there is the Special Building Phase. A player in Charlie’s (or Dan’s) position is more likely to do a similar deal like Bob did because he can spend the received resources in the Special Building Phase with a low to zero chance of someone (only Andrew could) interfering with a steal.

Storage Commission Deal: It’s Dan’s turn, he has 1 Wool on his hand and is about to end his turn. At the same time Andrew has 3 Lumber + 3 Ore + 2 Grain and really needs to build a city. Andrew knows that he will lose half of his resources if he throws a 7 which would be a disaster for him. Thus, he proposes to Dan to use Dan’s hand as a storage for a commission. This should work as follows:

Step 1: Andrew passes 2 Lumber to Dan and receives in return 1 Wool. Andrew’s hand is reduced to 7 resources which means he is out of danger.

Step 2: Dan ends his turn and Andrew rolls the dice. It doesn’t matter which number is thrown here.

Step 3: Andrew trades 1 Wool back to Dan and receives 1 Lumber.

Andrew ends up with 2 Lumber + 3 Ore + 2 Grain and may build his city now. Dan ends up with 1 Wool + 1 Lumber. Effectively, Dan offered his hand as a storage for Andrew to keep him out of danger and received a commission for his service. Again, the commission itself is subject to negotiation between those two players.

The Storage Commission Deal is most likely to work in 4 player games since it takes 4 dice rolls until the same player may spend his resources again. Sometimes it’s better to lose 1 resource rather than risking to lose 4.

Robber Protection Deal: It’s early in the game and Andrews’ turn. He throws a 7 and activates the robber. Instead of harassing the other players, he supposes a Robber Protection Deal. This should work as follows:

Step 1: He asks one of the other players, e.g. Charlie, not to use the robber against him the next time Charlie activates the robber himself. In return Andrew won’t use the robber against Charlie this time. If Charlie accepts, the other two players, Bob and Dan, are immediately facing a bigger threat by the robber since Charlie disappeared as a target for now.

Step 2: Andrew now proposes a similar deal to the other two players and they are likely to accept.

More often than not Andrew ends up being off each player’s target list for one time. The disadvantage is that Andrew won’t be able to steal a random card, but the advantages are very likely to outweigh them since he has the potential to escape the robber 3 times saving 3 random resources. Furthermore, Andrew’s hexes will not be blocked for a while which can be a huge advantage in the early game.

Conclusion: Those 3 techniques mentioned above although have a common downside. They require some level of trust between the players. There is no rule in Settlers of Catan which prevents the players to break an oral contract. But like in real life, it’s not very intelligent in the long run to piss people off by breaking deals.

Still, there are many other useful techniques out there which involve dealing with other players. It's up to a player's creativity to think of some new ones. 

Another useful tip: Try to have at a least 1 face-down Development Card on your side during the early game. It can be used as a psychological robber defense and it doesn’t matter which card it actually is. Other players will be hesitant to move the robber to you since they know that more often than not the face-down card is a Knight Card which can be used for a quick revenge. This strategy is especially useful since an early robber on one of your tiles dramatically reduces your winning chances.