Explanation of Button
Although the button (often abbreviated as BTN or BU) does not usually get to act first preflop, he is guaranteed the opportunity to act last postflop by default. For this reason, the button has an informational advantage (he always gets to see what his opponent does before he acts). The button is also in prime position to make blind-steal attempts preflop, since the small-blind and big-blind are to his direct left.
The button is hence considered the best position at the table, and the increased profitability of this position can easily be demonstrated through tracking software.
Note that while most variants of poker employ a button position, not all do. For example, Stud variants don’t utilize positions in the same way that Hold’em and Omaha do. Order is determined by the value of up-card rather than the position of a button disc at the table.
Example of Button used in a sentence -> (Hold’em). The button acts before the small blind preflop but after the cutoff.
How to Use Button as Part of Your Poker Strategy
Since the BTN is such an excellent steal position, we should be looking to open-raise aggressively in variants such as No-Limit Hold’em when given the opportunity. The general consensus is that a good No Limit Hold’em player will be open-raising around half of his buttons.
The BTN is also an excellent position to consider both three-betting and cold-calling aggressively, due to the guarantee of having absolute position postflop.
For a breakdown of the value of position and the different positions at a poker table, see the entry on Position.