Turn

The turn is the fourth card and the most expensive street. The pot has grown since the flop, the stacks have shrunk, and a bet of the same pot fraction is three times larger in dollars. One card is left: an unfinished hand either completes on the river or does not, and its odds are exact, 44 cards in the deck and so many of them useful.

This is where all-ins happen most often: the money on the table is enough for exactly one big bet, and whoever bets the turn usually decides the hand. A flop mistake costs a few dollars. A turn mistake costs the stack.

An example from session 12

K♣J♣ against Q♦Q♠, all-in on the turn. My share by then was 77.3%: one card to come, and almost all of them mine. Run twice, took +$56.81 against an EV of +$30.19. Betting the turn was right whatever the outcome; the size of the win was the deck's choice.

The same in business

The turn is the stage where a lot is already invested and not everything is known yet. The second funding round, the middle of construction, a year before break-even. Leaving is expensive, staying is expensive, and the decision here weighs more than any before it. Whoever planned only the flop makes his first real decision on the turn, when it costs the most.

The whole hand is in session 12: “A reputation is built faster than the case for it”.

The other terms are in the glossary.