J♦J♣ CO vs BB, river on Q♣ T♣ 7♥ 2♦ 2♣, 95 bb

Best play: Bet 40% pot

Why

Final board Q♣T♣7♥2♦2♣: the river club completes the flush and the deuce pairs the board, so villain's range is weighted toward clubs (flushes), Qx (top two), trip deuces, and bricked Tx/draws now air. Hero's J♦J♣ makes two pair, jacks and deuces, holding the J♣ as a weak flush blocker; it beats Tx, lower pairs and busted air but loses to every flush, Qx and trips. In position, a small 40% bet is thin value: it gets called by Tx and stubborn underpairs hero beats while the small size limits losses when a flush or Qx is lurking — overbetting would be reckless given how much of villain's range beats jacks-up.

Key idea

On a scary completed-flush board, size down with a vulnerable two pair — extract from the few worse hands while capping your loss to the many better ones.

Common mistake

Overbetting jacks-up on a flush-complete board, getting stacked by flushes and Qx and folding out only the rare worse hand.