Minimum Defense Frequency (MDF)

Definition

Minimum Defense Frequency (MDF) is how often you must continue (call or raise) to prevent an opponent from profiting with any two cards as a bluff.

MDF = Pot / (Pot + Bet)

The Logic Behind MDF

If you fold too much:

• Opponent bluffs 100% and always profits
• They don't need a hand to win

If you defend at MDF:

• Their bluffs break even
• They need real hands to profit

MDF Table

MDF Calculation

Example

Pot: $100 Villain bets: $75

MDF = 100 / (100 + 75) = 57%

You should defend with 57% of your range to deny villain profitable bluffs.

MDF vs Reality

⚠️ MDF is a baseline, not a command!

| When to Defend Less | When to Defend More | |--------------------|--------------------|| | Villain never bluffs | Villain over-bluffs | | Board favors their range | Board favors your range | | You're capped | You have nutted hands | | Position disadvantage | Position advantage |

Practical Application

River Defense Example

Pot: $200 Villain bets: $100 (50% pot) MDF: 67%

Your range: 30 hand combos

Must defend: 30 × 67% = 20 combos

Sort your range best to worst, keep the best 20 combos.

MDF Across Streets

💡 MDF is most useful on the river where ranges are clearest.

MDF ≠ Call Frequency

MDF is about continuing, not just calling:

Defending = Calling + Raising

Example

MDF is 60%. You could:

• Call 50%, Raise 10%
• Call 60%, Raise 0%
• Call 40%, Raise 20%

When MDF Doesn't Apply

❌ Ignore MDF when:

Alpha and MDF

Alpha (α) = Break-even bluff frequency MDF = 1 - α

They're two sides of the same coin.

Key Takeaway

MDF tells you how often to continue against bets to prevent auto-profit bluffs. But it's a starting point, not a rule—adjust based on villain's tendencies, board texture, and range dynamics.