OESD (open-ended straight draw)
A straight draw open at both ends — 8 outs
Definition
The OESD (open-ended straight draw) is a draw made of four consecutive cards: the straight completes at either end, for 8 outs. Probabilities: ~17% on the next card, ~31.5% from flop to river (the rule of 4 says 32%). It's one of the strongest draws in the game and a natural candidate for aggression: as a semi-bluff (raising a c-bet, barreling), it combines immediate fold equity with substantial real equity when called. Combined with a flush draw (combo draw, 15 outs), it exceeds 54% by the river — a favorite against top pair. Two practical nuances: check which end you're drawing to — completing the low end (the "ignorant end") can leave you behind a higher straight — and beware of two-tone boards where some of your outs also complete an opponent's flush. Not all 8-out draws are equal.
You call on the BTN with J♥T♥, flop 9♠8♦3♣. Any queen or seven completes your straight: 8 outs, ~31.5% by the river — and on the queen side, it's the nut straight. Raising the c-bet as a semi-bluff is a strong option: either the pot falls right away, or you play a big pot with real equity.