The book takes the button’s range, leaves it completely unchanged, and makes it act first on the flop. Nothing about the cards moves. Everything about the strategy does — and the gap between the two is what position is worth.
Hand info
MODIFIED SIMULATION. Preflop is real: you opened the button, the big blind called. On the flop the book flips who acts first while both players keep their original ranges — so you hold the button’s 49% range with no position. This cannot happen at a table; it is the book’s own thought experiment, built to price position with range held constant. A♣Q♦ is illustrative only — the question is about the range.
FLOP · 27.5BB EFFECTIVE
FLOP · FIRST TO ACT
6-max table. Hero is BTN with 27.5 big blinds effective. FLOP: 6c, 5d, 4s. FLOP · FIRST TO ACT. Hero holds Ac and Qd.
Hand history
Pre-flop
Flop
You opened the button with a standard 49% range and the big blind called with a standard 64% range. The flop is 6♣ 5♦ 4♠ — rainbow. Now the book flips the experiment: both players keep the exact ranges they just built, but you are the one who has to act first. This is a modified simulation, not a seat you can be dealt — it exists so the effect of position can be measured with the ranges held still.