Part: Part Two - Playing Styles & Starting Requirements

A big pair against a 3-bet

Pre-flop
Blinds 100 / 200Pot 2,600 (13 BB)COQ♠Q♦● 20,000 (100 BB)YOUyou opened to 500BTN● 20,000 (100 BB)3-bettor3-bets 1,800 (9 BB)SB● 20,000 (100 BB)posts 100 (0.5 BB)BB● 20,000 (100 BB)posts 200 (1 BB)D

You open to 500 from the cutoff with Q♠Q♦. The button - a competent, fairly aggressive player - three-bets. The blinds fold.

You opened pocket queens and a capable button three-bets to 1,800 (9 BB). Best play?

WhyFour-bet for value. Pocket queens are far too strong to fold to a single three-bet and play poorly as a flat call out of position. Four-betting builds the pot while you're ahead of most three-betting ranges and clarifies where you stand - only a four-bet shove from him should give you pause.
What happensYou four-bet to 4,400 (22 BB). He calls.  Pot: 9,100 (45.5 BB).
Flop
Heads-upPot 9,100 (45.5 BB)K♦9♣5♥COQ♠Q♦● 20,000 (100 BB)YOUoverpair? - no, a king flopsBTN● 20,000 (100 BB)3-bettorto actD

Flop: K♦ 9♣ 5♥ - an ugly card. A king is right in the range that calls a four-bet (A-K, K-K). You're first to act with about 14,000 (70 BB) behind.

A king flops - a card that hits his calling range hard. With Q-Q, best?

WhyCheck to control the pot. The king is one of the worst cards for queens: it smashes the A-K and K-K he called your four-bet with, while almost nothing worse continues against a big bet. Checking keeps the pot small and lets you fold cheaply if he bets, instead of stacking off an overpair into a better hand.
What happensYou check. He bets 4,500 (22.5 BB).
Turn
Heads-upPot 13,600 (68 BB)K♦9♣5♥3♠COQ♠Q♦● 20,000 (100 BB)YOUsecond-best one pairBTN● 20,000 (100 BB)3-bettorbet 4,500 (22.5 BB)D

He bets on the king-high board. The turn is irrelevant to your decision - the question is whether queens are good.

Facing a 4,500 (22.5 BB) bet on a king-high board in a four-bet pot. Your queens are…

WhyFold. In a four-bet pot a king-high flop crushes your opponent's continuing range, and a bet here represents exactly the kings and ace-kings you fear. Queens were a great hand pre-flop and a weak one now. Surrender and keep your stack - overpairs are not automatic.
What happensYou fold; he shows A-K.  You lost the minimum on a bad board.
You correctly four-bet queens for value pre-flop, then refused to marry them when a king arrived in a four-bet pot. Big pairs win money by getting value when ahead and folding when the board and the action say you're beat.

Big pairs are not unfoldable: four-bet them for value pre-flop, but respect a board and a line that smashes your opponent's range.