A♥4♣ BTN vs BB, preflop, 65 bb

Best play: Raise / 3-bet

Why

Hero is BTN first to act with A4o at 65bb. The HU BTN opens ~80-100% of hands, so even a weak offsuit ace is a standard open. A4o earns its raise through the ace itself: it is a top-card holding that blocks villain AA/AK, flops top pair often, and steals the blinds at a high rate against a BB that cannot defend everything. It is not as strong as the suited aces because it lacks flush and clean straight equity, so play it as a steal and do not overcommit when called. Still, folding or limping it on a HU button is a leak; raise (open) is correct.

Key idea

Even bare offsuit aces open on the HU button because the ace blocker plus top-pair potential clear the wide opening bar. Treat A4o as a fold-equity steal, not a hand to stack off light postflop.

Common mistake

Folding A4o thinking it is too weak. HU it is a fine open; the bigger leak is the opposite, overplaying it postflop and stacking off when the ace pairs against a stronger ace.