Part: Part Twelve - Heads-Up

Raise, don't limp

Pre-flop
Heads-up • Blinds 400 / 800Pot 1,200 (1.5 BB)BTNQ♦7♣● 20,000 (25 BB)YOUfirst to actBB● 20,000 (25 BB)Opponentposts 800 (1 BB)D

Heads-up, on the button with Q♦7♣.

Heads-up button with Q♦7♣. Best?

WhyRaise. From the heads-up button you raise a very wide range to apply pressure and take the initiative - limping is passive and lets the big blind realize equity cheaply. Q-7 offsuit is a routine raise.
What happensYou raise; the opponent folds or plays a pot out of position.  Aggression, not limping.
The heads-up button raises a huge range - limping surrenders the initiative that your positional edge is built on.

Raise the heads-up button rather than limping - apply constant pressure and keep the initiative.