Guides / Big Blind Defense
Big Blind Defense: How to Build a Calling and Shoving Range
Published Updated How these ranges are solved
The big blind is the one seat that never has to open a pot to see action - it only ever reacts to a price someone else has already set. That changes the question. An opening range asks "which hands are worth starting a pot with?" A big blind range asks "which hands are worth continuing with, now that I know the price and who set it?"
A continuing range, not an opening range
Every chart on this page is the big blind's continuing range - call or shove, whichever the solver prefers, combined into one non-fold frequency per hand. At these stack depths there's rarely a real difference between the two: calling and shoving both put effectively all your chips at risk once you're short, so the meaningful line isn't call-vs-shove, it's continue-vs-fold.
Why the opener matters
The same big blind, the same 10bb effective stack, against two different opens. Under the gun has the whole table left to act behind it, so an under-the-gun open is a strong range on average - the big blind can only afford to continue with 18% of hands. The button opens last, with nothing but the blinds behind it, so a button open is full of hands that only raised because no one was left to punish it - the big blind can profitably continue with 31% of hands against that, roughly 72% wider than against the tighter open.
vs. Under the Gun open - 18%
vs. Button open - 31%
Depth widens this further
Both ranges get meaningfully wider the shorter the stacks get, for the same reason covered in the stack-depth guide: less behind means a call or shove risks less in absolute terms, and the opener's range doesn't get proportionally stronger just because the stacks got shorter. At 5bb effective the same two spots continue closer to a quarter of all hands each - defense against an early-position open and a button open converge as everyone's stack gets short enough that position matters less than survival.
Going the other way tightens it just as sharply. The big blind's 20bb chart against a button open continues with a much narrower slice than the 10bb one above, for the mirror-image reason: the pot you are playing for has not grown, but the stack you have to risk to contest it has doubled. Same opener, same position, twice the price.
See the big blind's defending range against every position and depth, not just these two.
Common questions
- Should you defend wider against a button open than an under-the-gun open?
- Yes, substantially. Under the gun has the whole table left to act behind it, so its opening range is strong on average. The button opens last with only the blinds behind it - at the same 10bb effective stack the big blind can profitably continue far wider against the button.