A♠Q♠ CO vs BB, river on J♦ 8♠ 5♣ 9♠ 2♦, 90 bb

Best play: Check

Why

River, board J‑8‑5‑9‑2 with only two spades, so hero's A‑Q of spades is exactly ace-high: no pair, no straight, no flush. Against the BB's capped checked-down range this hand beats only busted bluffs and loses to every pair, so a 40% 'thin value' bet has no worse made hand to call it. The standard play is to give up and take showdown; A-high cannot bet for value here.

Key idea

On the river a value bet needs a worse made hand to call. Ace-high beats only bluffs, so it belongs in the check-and-showdown bucket, not the value-betting bucket.

Common mistake

Treating a strong-looking ace-high holding as 'thin value' and betting it, when in fact only better hands call and worse hands fold.