Part: Part Six - Betting After the Flop

Double-barreling a scare card

Flop
Heads-upPot 1,300 (6.5 BB)Q♣7♦3♠COA♥K♥● 25,000 (125 BB)YOUtwo overcards + backdoorsBB● 25,000 (125 BB)Big blindchecksD

You opened and the big blind called. Flop Q♣ 7♦ 3♠ - you have A-K high. He checks.

You miss but hold two overcards and the betting lead. Best?

WhyA dry queen-high flop misses his calling range far more than it hits, and you hold two overcards plus a backdoor draw - so a bet folds out his air and takes the pot uncontested a lot. Betting 700 also builds the story for a turn barrel; checking surrenders the initiative with a hand that can still improve.
What happensYou bet 700; the big blind calls. Pot: 2,700 (13.5 BB).
Turn
Heads-upPot 2,700 (13.5 BB)Q♣7♦3♠K♦COA♥K♥● 25,000 (125 BB)YOUa strong scare card fallsBB● 25,000 (125 BB)Big blindchecksD

Turn K♦ - you pair your king (now top pair, top kicker), and it's also a scary card for a caller. He checks.

The king both improves you and threatens his range. Best?

WhyThe king is one of the best cards in the deck for you - an overcard you would routinely be betting, and it just handed you top pair, top kicker on top of that. Bet 2,000 to get value from worse pairs and draws and to fold out the middling hands that cannot stand a second barrel.
What happensYou bet 2,000; he folds. The barrel takes it - and with top pair, top kicker you would have been glad to get called, too.
You c-bet the flop, then the turn king both improved you and hit a card you would often have, so you kept firing. The best double-barrel cards favor your range, and here that card doubled as top pair.

Barrel the turn cards that live in your range - the overcards you would credibly hold. They make your story believable, price out his marginal hands, and sometimes hand you the best hand too.