Phases of Attack

Back to: LSAT Logic Games

As we move on through our logic games introduction, we will now take a look at the phases of solving a game.

1. Assemble Your Game Pieces and Board into a Main Diagram

The first phase of any game is understanding your variables. Which variable set are you going to use for the board (the base where your empty spots are located)? Which variable set is going to become the pieces (the pieces you’ll be putting into your empty spots)?

When this is all drawn out, it becomes your main diagram. This main diagram is where you want to draw a diagrammed (visual) version of all the rules that you are given in the prompt.

With basic ordering games, it’s usually very straightforward. You use the variable set that already has an inherent order as your base. If there are 6 weeks in a row, that is your base. If there are 9 days in a row, that is your base. Here’s a look at an example: A delivery truck is making deliveries on each of six consecutive days, from Monday through Saturday. The items to be delivered are Fencing, Grain, Hardware, Livestock, Machinery, and Produce. Only one item will be delivered each day.

Which variables are your base? Which are the game pieces?

The days have an inherent order. For that reason, it will be much better if they are your base. List the game pieces up to the left, and the game board (base), right in the middle of your blank space, like this:

Imagine trying to do it the other way, with the items are your base and the weeks as the moving parts:

Trying to work with that would be a major headache. Say you had a rule saying that F had to be delivered before G. You would always have to check to make sure the day placed above F was earlier than the day placed above G: F must be delivered before G

The rule is violated here, yet seeing that is way more mental work to check than simply confirming whether or not the F is to the left of the G.

Reduce the strain on your brain. Use the variables that are already ordered as your base.

This phase is where we get the broad possibilities of the game outlined. Six pieces going into six spots is a lot of possibilities, but, as we saw before, it’s going to get much more limited when we thrown in the rules. That’s phase two…

2. Diagram The Rules

Next, it’s time to get your rules in place. For this process, there are several maxims I want you to remember.

1. Every rule and condition should be written down somehow

Your diagramming of the game should have written in it every single thing you need to know to solve the game. You’ve already taken one look at this process in the diagramming introduction. The goal is that after you are all done diagramming you don’t have any need to look back at the written prompt. It is all mapped out in a way that you understand it all and can work with it.

2. It’s best to get information diagrammed internally

What I mean by this is that, where possible, it’s usually best to get information into the visual part of your diagram, rather than just written off on the side. For example, if within an ordering of six things I know that a variable J can’t go 4th, I want to draw that right into the main diagram, like this.

The internal visual reminder will be a much more effective way of remembering the rule for the vast majority of people. It’s okay to write the rule on the side too, as I did here. Just don’t only write it there. When you can get it a rule right into the game board you should do so.

Keep in mind that a lot of common rule types are best just written off to the side, as there would be no helpful way to draw them into the game board. We’ll discuss in depth where to write certain rule types. Keep this distinction of internal vs. external in mind when you think about diagramming rules.

3. Visual representations are usually better than words

Let’s consider a hypothetical rule type that we will encounter all the time in logic games: some item is before another item. Here is the rule: “X comes before Y”. Given a choice about how to write that, which of these two representations do you prefer? X comes before Y

I’m guessing the first one will be your choice. It’s much easier to think, “Okay, from now on I just have to see them in that order.” Even if you are rare individual who thinks you might do better with the first method, it’s time to get out of the habit now. Later, we are going to need to link a lot of these rules together, and using a visual representation is the only good way to do it.

A good visual representation isn’t always possible with every type of rule you encounter, but when it can be done it is best to do it.

Keep these three things in mind as you diagram:

1. Represent (write) everything somehow

2. Diagram internally when possible

3. Diagram visually when possible

…and you’ll end up with very useful diagrams. Remember, the games are actually designed by the test makers to work with visual diagrams. If you don’t use visual representations, and try to do everything in your head, you’ll be exerting way more mental effort than is necessary. On the LSAT, you don’t have to impress anybody with your mental acrobatics. You have to get the problems right as fast as possible. Make it easy on yourself.

3. Link rules

Rules are not meant to be understood in isolation. Look at these three rules in a hypothetical ordering game setup where you are ordering six variables, Q, R, T, U, S, and V: T will come later in the order than R R will come later in the order than Q R is immediately preceded by U

You might start out diagramming these like this:

That could work fine for solving the game, but isn’t it much easier to just look at this?

Combine rules when you can. Now, for the rest of the game, I can simply make sure any order I make follows this nice simple Q—UR—T chain, rather than looking at three separate rules.

4. Make Inferences

As I said, each rule you tack on will have the effect of further narrowing the possibilities. When you are done diagramming your rules, and linking them up, it’s time to consider what the rules can tell you about the order. These deductions are called inferences, and they are really the soul of solving LSAT logic games. Here’s an example of a classic inference technique. It’s not an easy one for beginners to spot, but believe me, you will have this mastered eventually.

Let’s do a game with just five pieces and five spaces where the game pieces can go.

Now here’s a few rules: A is before B C is before E D is fourth

Here is that diagrammed:

Now, where do we go from here? From just these rules, you can add in a very simple kind of inference. Look at the rule that “A is before B”. Where can’t the A go as a result of that rule. Where can’t the B go? The A can’t go last, otherwise, there is no room for the B to fit in the order. Similarly, the B can’t go in the 1 spot, otherwise, there is no room for the A. You can make these same inferences with the “C is before E” rule. Here is all this captured in your diagram:

Those inferences just by themselves may not always be super-helpful, but they often lead to other inferences. Here, there are more inferences we can make. Think about what remaining variables can go in the first and last spots.

That first spot has to be either A or C. That “A/C” is how we write that A or C has to be there. Similarly, B and E are the only two that can go in the last spot.

Working with this diagram will be much faster than just looking at this one:

Imagine now a question tells you, “If B is second, then which of the following could be true”, you will now know immediately that E is last, in the 5 spot.

There are a ton of different kinds of inferences, so we’ll be talking about them in great detail later on. For now, just understand that getting your rules on paper and linked up isn’t the end of the line. You’ll have to see when you can make further deductions about how the order is restricted.

In games, you have to walk a tightrope between spending too much time looking for inferences, or not spending enough time. It’s one of the hardest aspects of games to master. When watching our explanation videos, pay attention to how we handle this part of the thought process.

5. Attack the Questions

Solving the actual questions is a big mix of making more diagrams and more inferences, as well as sometimes using trial and error. Before we talk about it in the abstract, it’s best to see the process a few times. The details will be handled in later lessons.

To help with that, here is a whiteboard style video where we take you through an ordering game and look closely at the different phases of attack.

PT 3 Game 2 Walkthrough

This basic ordering game comes from a very early PT. This one isn’t published in hard-copy form, but you can download it in various places. However, you do not need to have the game to watch the video and get a look at how the phases of attack work in a full game. At this point, you are still just getting a broad picture. You will begin getting your hands on the game-solving process in the next lesson! Here, pay attention to the phases of attack and look at how the reasoning process unfolds.

Consider this the end of your introduction. We’ll be taking a closer look at the questions themselves later on. Now, it’s time to start mastering the specific diagramming techniques you need to attack the questions. As you saw in the examples up to now, there are a bunch of different kinds of rules on logic games. We can give you a weapon in your arsenal to handle any rule you encounter.