Many players claim to make the perfect plays at all times, but very few understand just what that means. Today, I’ll be offering a rather unique way of determining how you should play the cards you’re dealt to increase your win percentage and improve your game. While it is impossible to make the perfect play every time in every situation, a clear head and a logical, mathematical approach to the game will offer you the correct move in any situation more often than not.

First, I’d like to offer credit for this theory to a man named Dan Harrington: a famous and highly respected professional poker player and author of Harrington on Hold ‘em, a book I attribute the following thought process to. While the Yu-Gi-Oh! TCG and poker are two different games, becoming a professional player in each requires the same skills and concepts. Anyone who has played with me knows I spend my matches shuffling poker chips and often use poker analogies to explain Yu-Gi-Oh! predicaments.

I can’t speak for all players, but I can share a formula I’ve used to make the correct plays against opponents I’ve never played before. This is actually a way of reading opponents which allows you to make the most informed move you possibly can in any situation—a skill I consider vital to becoming a great player. Just consider the Yu-Gi-Oh! television show episode, in which Yugi played against Pegasus (who could read his mind, allowing him to know every card he played). Imagine having an ability to read opponents that was almost as consistent as Pegasus’ Millennium Eye: this will give you an idea of how useful correct reads can be.

This theory is best demonstrated through example. Imagine you have to choose between two plays. You have Cyber Dragon and D. D. Assailant in your hand, and your opponent has Il Blud, Spirit Reaper special summoned by the Blud, and a single back-row card, but no additional Zombies in his or her graveyard. After looking through your opponent’s graveyard, you realize that player has not used Mirror Force yet (checking for Mirror Force is a practice that, if you don’t already employ it, I encourage you to begin).

You have, in general, two strong options to choose between: you can special summon Cyber Dragon and normal summon the D. D. Assailant (attacking the Il Blud and destroying both monsters), and then attack for additional damage; or you could only summon your Cyber Dragon, attack the Il Blud, and set the D. D. Assailant if your attack is deflected. Both of these moves are strong plays that could be rewarded. Normally, a player will make the same decision (the decision between being conservative and aggressive) every time. However, the best players will vary their moves depending upon the situations that arise.

Now suppose this is the third game of the match and you have a lot of information about your opponent’s deck. First of all, say he or she runs Sakuretsu Armor, opting not to play a triple Dust Tornado lineup instead. It’s late game, and this move is crucial since it could make all the difference. Let’s assume your opponent has only 2100 life points to make things interesting. Attacking now with both monsters could win you the game, but it could also lose you the game.

However, more information still needs to be ascertained before you can make an informed decision. How many cards does your opponent have in hand and how many cards are left in his or her deck? If your opponent has four cards in hand and the Dragon and Assailant are all you have left, I’ll almost always choose to get aggressive at this point. Your opponent will most likely be able to respond to anything you do because of his or her overwhelming options, so you’ll need to take this game via damage as the aggressive player. However, suppose your opponent is just as down and out as you, with no cards in hand. This complicates the situation, because the match could actually ride on this decision.

Here’s where the math begins. Your opponent has nineteen cards left in his or her deck and has shown no signs of having a Mirror Force in the past. If this card the opponent has set is the all-punishing Mirror Force, it was just drawn last turn. Now the math begins . . .

I’ll begin by saying most of this is done with estimates. You almost never know your opponent’s complete decklist, and it would still be nearly impossible to make the math perfect if you did. However, through testing with popular decks and gaining a general understanding of how every deck works, you’ll be able to make decently accurate guesses.

Remember, the back row can’t be many things. Any Book of Life would have been played, along with many more cards. In poker you always factor in at least a ten percent chance that any move is a bluff. However, in Yu-Gi-Oh! this number is incredibly high. If your opponent is playing Zombies, about one-eighth of his or her deck could have been set off the draw with no negative consequences. Never forget to factor this in. Of course, any card in the opponent’s hand could have been set as a bluff, so I’ll give the card about a 50 percent chance of being a red herring. If it is a bluff, attacking would yield the destruction of an extra card beyond your own and 2100 damage (assuming you attack with D. D. Assailant into the Il Blud, the correct move). According to general convention, every card is worth about 2000 life points. Let’s call the extra card you’re removing from the field 1 point, and the 2100 damage a second point for a total of 2.

Next, we move onto the chances that the card is not Mirror Force, but something else that would thwart a single monster attack. Here, I’m speaking of Sakuretsu Armor, which will actually make attacking with both monsters a much better play than not. Assuming the opponent runs three, there’s a fifteen percent chance he or she drew it the turn before (three of the remaining 20). Of course, Sakuretsus could have been saved in the player’s hand from turns previous. Here, I’ll award about a 30 percent chance the card is Sakuretsu Armor. If it is Sakuretsu, then attacking with both monsters would still get rid of two of the opponent’s cards to your one, taking all the cards from the field and leaving both players without anything. Since you’re up one card, that’s 1 point under this system,

Finally, there’s a one in 20 chance the card is indeed Mirror Force, drawn fresh off the top of the deck. Most players don’t hold onto it for very long, so it wouldn’t stick around for many turns. At most, I’ll offer it a 20 percent chance, being very generous as a generally conservative player. If the other player activates Mirror Force, you’ll lose both your monsters, take a card loss in the long run, and be given 2100 damage (at least) to enjoy. That’s -2 points overall, and probably more when the opponent draws next turn. Also, you’ll be topdecking at that point, meaning you’ll be far behind. For this reason, I’ll definitely penalize myself another point, making the negative result of the card being a Mirror Force a -3 overall.

Now, put that math together to make your educated guess at the correct play. So 2/10 multiplied by -3 is -6/10, 3/10 multiplied by 1 is obviously +3/10, and 5/10 multiplied by 2 is +1. That means -6/10, +3/10, and +1 are the outcomes of each move multiplied by their chances of occurring. Adding those numbers together gives you +7/10, meaning the aggressive move is likely to be profitable in the long run.

Therefore, you choose to attack with both monsters, despite the risk that the card is a Mirror Force.

Pretend now that your opponent flips the card and it is, in fact, his or her single copy of Mirror Force, winning the game as a result. What does that mean? That means that, despite the incredible amount of math and the fact that you made the “theoretical” correct decision, you lost the game. However, remember that making the correct play every time will mean that you will win the highest percentage possible of your games. Although you were “unlucky” here, you’ve already admitted that there was a 20 percent chance of this outcome. Just remember that the other 80 percent of the time, you’ll be winning matches as a result. This theory can’t be used for every move, but it is highly useful.

Additionally, over time, you’ll gather reads on your opponents. Occasionally, you’ll just know when your opponent has something. Personally, I follow these instincts. However, remember that while your judgment and intuition can be wrong, mathematics cannot. I’ll actually use this formula only about twice a match (and I don’t bother thinking this hard when I’m not playing in a major tournament). However, being able to do this when the moment calls for it is a skill which can separate you from all the other players who can’t.

We all need our taglines, and I think I’m beginning to adopt one. You aren’t psychic, but you can always make the mathematically perfect move. The Yu-Gi-Oh! TCG isn’t a game in which the best player always wins, and no amount of preparation can give you a definite victory. However, the better player will be the one who, over time, shows the highest win percentage. Just remember to keep improving your chances of winning, one percent at a time.

—Ryan Murphy