A♦5♦ BB vs SB, river on K♠ T♥ 7♠ 6♣ 2♠, 90 bb

Best play: Check

Why

River (K T 7 6 2). Hero is the IP BB and the board shows three spades (K-spade, 7-spade, 2-spade), but A-diamond/5-diamond holds NO spade, so there is no flush and no pair: hero has only ace-high. A-high beats nothing but pure air, and with zero spade in hand hero cannot even claim the nut-flush blocker that justifies an overbet bluff. Pumping 120% pot turns a free showdown into a spew that only worse air folds and every made hand calls; the polar overbet wants near-nuts value or a real blocker bluff, and ace-high is neither.

Key idea

On the river your hand is final: count every suit before you bluff. An overbet bluff needs blockers that remove villain's calls; holding no card of the flush suit means you block nothing, so a check to take the free showdown is the only sane line with ace-high.

Common mistake

Seeing the ace and 'a draw board' and firing an overbet as a bluff, forgetting it is the river (no outs left) and that with no spade hero blocks none of villain's flushes or strong made hands.