Remember my previous post about the Pair Principle? Here’s another one from Phil Gordon’s toolbox. It is called the A-X rule.
The rule itself is very simple:
If your ace kicker card has a higher value than the number of players that are left to act after you, you are a slight favourite.
It sounds too simple, right? It is, and in my view its use cases are limited. I would use it only in a regular paced game with less than ten blinds left in a shove or fold situation.
What’s the math?
This time we don’t need to make any calculations during a hand. We only need to convince ourselves that this might work.
I tried this with an equity calculator and this is what I found out:
Equity against one player when holding… A2o is (52%), A2s is (56%)
Equity against two players when holding… A3o is (35%), A3s is (39%)
Equity against three players when holding… A4o is (27%), A4s is (30%)
Equity against four players when holding… A5o is (20%), A5s is (25%)
Let’s increase our kicker value by one and see what happens.
Equity against one player when holding… A3o is (52%), A3s is (57%)
Equity against two players when holding… A4o is (36%), A4s is (39%)
Equity against three players when holding… A5o is (25%), A5s is (29%)
Equity against four players when holding… A6o is (20%), A6s is (23%)
Very little change to be seen. Now we kick our kicker once more.
Equity against one player when holding… A4o is (57%), A4s is (59%)
Equity against two players when holding… A5o is (35%), A5s is (38%)
Equity against three players when holding… A6o is (25%), A6s is (30%)
Equity against four players when holding… A7o is (21%), A7s is (26%)
Since we don’t know our opponents cards we simply divide the rest of the equity with the number of players left to act.
For example:
holding A3o against two opponents leaves (100-35)/2 which equals 32.5% equity for each opponent, or…
holding A5o against four opponents leaves (100-20)/4 which equals 20% equity for each. At worst it’s a coin flip.
Would I shove?
The A-X rule has some merit to it although it has been criticized around the internet for being a crude tool. I haven’t checked but a solver might give a different opinion about these shoves.
Against one or two players with just few blinds in front of me, sure I would shove. Anything more than that starts to feel tricky. A low pair could simply beat us if our luck runs out. But as always, everything in poker depends from different variables in our table which we need to take into account.