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FlopZoom Tutorials: Basic
M Inflection Points

We're going to continue our examination of the current hand tutorial example. villain_d was eliminated from this tournament on hand 43. But did she really need to move in with king-ten? His M will tell us.

Displaying M
Just click the "Inflection Points" button along the bottom of the session pane. Now you can see the Magriel-Harrington M for up to four players. Briefly, your M is the ratio of your stack to the pre-deal pot size. Divide your chip count by the number of chips in the big blind + small blind + everyone's antes (if there are any antes at the time) and that's your M.

We've selected villain_d and his stack line appears in blue here. As we can see, his M had dropped below 5. According to "Harrington on Hold'em Volume II" she was in the "red zone" and needed to get lucky and immediately double up. She didn't, and his stack drops to 0 on his last hand.

Know Your M
The concept of M and the various "inflection points" (M ranges) is extremely important in tournament poker. Although the M concept was originated by professional poker and backgammon player Paul Magriel, Dan Harrington has done the most to popularize it. We highly recommend his "Harrington on Hold'em" book series.

You may have seen Mr. Harrington on the ESPN telecasts of the 1995, 2003, 2004 World Series of Poker Main Event final tables. He won the Main Event in 1995 and finished 3rd in 2003 and 4th in 2004. His books clearly and concisely describe the mathematics and logic behind M and inflection points, and how they both should dictate your playing style.

What Are Inflection Points?
Mr. Harrington's books do an incredibly good job of developing the concepts of M, zones, inflection points, and how to play tournaments using these concepts. We'll try to quickly paraphrase the main points here.

In a nutshell, as your M changes, you should change your playing style. Different ranges of M values, from deep stacked to micro stacked, dictate which hands you should play and for how much of your stack. For example, if your M is less than 5 and other players' M is much larger, you'll need to move in and hope to double or triple if you can. You're probably going to get called, since the bigger stacks can afford to lose some chips in an attempt to knock you out.

The different ranges of M are called "zones":

Green ZoneM = 20 or more
Yellow ZoneM = 10 to 20
Orange ZoneM = 6 to 10
Red ZoneM = 1 to 5
Dead ZoneM < 1

As your M value transitions between zones, you'll need to change your playing style. The transitions between zones are what Mr. Harrington calls "inflection points." You'll pass through inflection points as your stack increases or decreases and as the blinds increase.

So what, exactly, is FlopZoom showing you? For all players you've selected, it shows their M at the start of the first and last hands in range, their maximum M in range, and their M whenever they're at an inflection point. (We say "in range" because you can select all hands in the tournament or just ten hands surrounding the current hand.) We've also added a few extra deep stack inflection points of our own, at M values of 100, 200, and 500.

In some of the screenshots below, you'll see "M=33" at the first hand of the tournament in the all hands views. Not an inflection point, but an interesting fact to note. You can also spot "M=41" in the all hands view and "M=22" in the ten hands view on villain_c's stack line.

Finding Key Players
To show the stack of the player who busted villain_d, we click back to the playback pane and see who won the hand by clicking the river button and the next action button to the end of the hand. It was villain_c. We could have selected players from the player name menus until we found one whose stack increased on villain_d's bustout hand. But this could take a long time if there were many players in the tournament.

We can now click back to the sessions pane and select villain_c. We've selected him from the red popup menu and his graph appears in red. Our hero eventually busted him to win the tournament in this example.

We've selected a fourth player to max out our M graphs here. As you can see, it can get pretty congested with all four players and many inflection points.

You can zoom in and get a better view of things by clicking the show ten button at the bottom of the display. Here we've done that and also clicked the opponent count button.


Results and Big Blinds
FlopZoom can show you how much you or any player won or lost in a ring game session. Just click the "Results" button at the bottom of the sessions pane and it will appear in the upper left corner of the stacks and pots graphs. In a ring game you may prefer to think of stack sizes in terms of big blinds instead of M. This is probably also true in limit games, both tournament and ring. Here's an example of a ring game stack graph showing results and BB.

The dotted section of the blue stack graph for player "ft test player 2000" indicates hands on which that player was sitting out. We thought it would be helpful to differentiate passively folding while sitting out from actively folding cards while playing.


Know your M in tournaments. It's crucial, and it is a major factor in determining how you play. We added it to FlopZoom's session pane to show you if and when you should have changed your playing style as the blinds went up and as you won and lost key pots. And so you can see whether or not other players understand the M concept and change their styles as their M changes.

The results window and the BB captions to the stack graph are, well, results-oriented. How well you play is far more important than how you're running or how much you won or lost. But the money you win and lose in ring games can be an indicator of whether you're playing in the right games against the right opponents. Look for much more about ring game play and results in future versions of FlopZoom.

Basic Tutorials:
Playback Pane | Session Pane | Current Hand | M Inflection Points