he who strikes the first blow will win; whoever strikes first gains(/has) the advantage; to take the initiative is to gain the upper hand; offence is the best defence; it is best to take (/make) the running
❍ ～。她伸手拽出了橹子枪，照着先上来的那个当的一家伙，…… (冯志《敌后武工队》276) Better strike the first blow. She whipped out her gun and snapped off a shot at the one climbing the embankment./“～！”我默默地下定决心。(杨得志《强渡大渡河》) “He who strikes the first blow will be the winner，” I decided.
❍ 卖出或是买进，～！(茅盾《子夜》233) Whether you’re buying or selling,remember the early bird gets the worm!/我待要～。(《关汉卿戏剧集·关大王独赴单刀会》244) The first to strike will win.
先下手为强
he who launches a preemptive strike gains the upper hand;he who strikes first gains the advantage;catch the ball before the bound
～，后下手遭殃he who strikes first prevails;he who strikes late fails
先下手为强xiān xià shǒu wéi qiánɡ
先下手的就可以获取优势。take the initiative is to gain the upper hand, the best defense is offense, The early bird gets the worm.