Overbet

The button holds A♦K♦ and calls a preflop raise. The board runs Q♦ 9♣ 8♦ 5♣ T♦. That river ten of diamonds does two jobs at once: it fills a flush and it completes 7-8-9-T-J for anyone holding J-7. The big blind, sitting on J♠7♠, now has a jack-high straight — a hand nobody folds. The button, holding the nut flush, skips the standard two-thirds-pot bet and fires one and a half times the pot. The same river completes nothing for plenty of other hands — a busted flush draw, a pair that ran out of outs — so the same huge bet can stand for a monster or pure air.

Overbets work on math, not aggression for its own sake. As a bluff, a bet of one and a half pots has to take the pot down three times in five just to break even. Against a hand that can't fold, the bigger the bet, the more it collects. One size does two jobs: it charges full price to the hands that have to call, and it hides among the missed draws, so an opponent can never be sure which button they're facing. The bet stops meaning 'I have it' and starts meaning 'guess.'

The common beginner mistake is lopsided sizing — overbetting only with the nuts. Do it consistently and the size becomes a tell: good opponents fold everything but the nuts, and the overbet earns no more than a normal bet would. The fix is bringing some busted draws to that same big sizing, so the threat behind it stays real. The opposite mistake is calling every overbet on pot odds alone, against someone who only sizes up for value.