Chemistry plays a vital part in how your Ultimate Team performs in FIFA 13. If you're new to the game, you'll need to know that each team you make or play against has a chemistry rating between 0 and 100, 100 being the best. The higher chemistry you have, the better your team moves the ball around. With higher chemistry, your players will make smarter runs and players will understand where the others are going.
Also take a look at my full review of the FUT Millionaire Guide, which has a full section on strategy and chemistry. If you're here, you're probably the kind of player who likes to tinker with his squad, and the FUT Millionaire Guide spends a lot of time on that one topic.
Between any two players who are next to each other, there is a chemistry bond (or not) that can be determined by a number of different factors. For example, if your two strikers play for the same club, that chemistry bond will be strong and your overall chemistry will receive a boost from it. The factors that dictate your chemistry are explained below, so read on to learn how you can optimize your team's chemistry in FIFA 13 Ultimate Team!
Having players that are of the same nationality will benefit your chemistry greatly. This applies in side-by-side players, but they don't necessarily have to be next to each other to give you the chemistry boost. If any of your players have the same nationality as your manager, you will receive a chemistry boost for that, so try to use a manager who best matches the nationalities (or another factor) of your players.
As mentioned above, having players from the same club in your squad will provide a chemistry boost. This functions exactly like the nationality factor does, so read there for further explanation.
If you're really looking to maximize your chemistry, then you should look into making sure your players and manager agree with the formation you're using. You can check what any player or manager's preferred formation is by clicking the right stick on their card to bring up the details page. If you're playing 4-3-3, you'll want to make sure everyone on your team prefers 4-3-3 to optimize chemistry. If they don't prefer that formation naturally, then you can buy cards that will “train†your player/manager to change their preferred formation, but they can be pricey.
While it may be strategically advantageous to play certain players out of position, it will hurt your chemistry significantly. Each player has a preferred formation, but you can change that much like you can change formation with training cards. However, this time you can't change any position to any other position. You are confined to the “spine,†positionally. This means, you can only interchange your LW, LM, and LF players with these training cards. The right side works the same way. You get the gist.
Of course you don't have to follow these rules completely. By playing around with chemistry yourself, you will notice that the system is rather lenient in FIFA 13. One of the most challenging things is still to create a diverse and fun squad while still keeping your chemistry at 100.