J♠9♠ SB vs BTN, river on Q♣ 9♦ 6♣ 2♠ A♦, 85 bb

Best play: Check

Why

River Q 9 6 2 A, no flush (you hold only J and 9 of spades). Your J9s makes middle pair of nines with a jack kicker, a marginal bluff‑catcher once the ace and queen are on board. As the OOP SB into the BTN, overbetting middle pair gets folds from worse and calls only from Qx, Ax and better, so the recommended overbet turns a showdown hand into a money-loser.

Key idea

Middle pair on a river with overcards is a bluff‑catcher; check it down rather than overbet.

Common mistake

Overbetting middle pair as if it were value, when only better hands continue.