strategy
Alpha (bluff break-even)
Also: bluff break-even percentage
The percentage of the time a bluff needs to work to break even: bet ÷ (bet + pot). It is the mirror image of minimum defence frequency.
Example. Bluffing €75 into a €150 pot has alpha 75 ÷ 225 = 33%: if the opponent folds more than a third of the time the bluff prints money.
A pot-sized bluff needs to succeed 50% of the time; a half-pot bluff only 33%; a 2x overbet needs 67%. Alpha tells the bettor how often the opponent must fold; MDF tells the defender how often they must not. Because alpha only counts fold equity, hands with extra equity when called (semi-bluffs) need to work less often than the formula says.