Literally: before – hand – certain – win
Alternately: Who strikes first, wins. The early bird gets the worm. This phrase may be used to espouse a “first strike” mentality as a general philosophy, or to describe the particulars of a situation that calls for quick and decisive action. Often, but not universally, used in combat situations or simulations such as martial arts or board games.
Notes: In the karate community, there’s a countering bit of wisdom that says 空手に先手無し (karate ni sente nashi): “In karate, there is no ‘first strike.’” This can be interpreted in different ways, but one of them is that it actually doesn’t matter who moves first. This might be because block-attack combos are the bread and butter of your style, or it might be because of the value of waiting for your opponent to show their intention and then attacking into their prep. But in any case, the only thing that really matters is not who starts the action, but who finishes it.