アーティファクト
エンジン始動!
このアーティファクトが戦場に出たとき、対戦相手がコントロールしていて土地でないパーマネント1つを対象とする。このアーティファクトが戦場を離れるまで、それを追放する。
最高速度 —

:あなたがコントロールしていてクリーチャーや機体である1体を対象とする。それの上に+1/+1カウンター1個を置く。起動はソーサリーとしてのみ行う。
Each player tracks their speed (or lack thereof) separately. Increasing your speed has no effect on whether another player has speed.
A player “has max speed” if their speed is 4.
If an effect needs to know what a player’s speed is and that player doesn’t have a speed, their speed is considered 0.
Your speed doesn’t change until a spell or ability says so, such as the inherent triggered ability that cares about opponents losing life during your turn. Notably, losing control of permanents with start your engines! doesn’t affect your speed.
“Max speed — [ability]” means “As long as you have max speed, this object has [ability].” If the granted ability functions in a zone other than the battlefield, the max speed ability does too.
Start your engines! isn’t a triggered ability. Increasing your speed to 1 is something that happens as a state-based action as soon as you control a permanent with the ability. Notably, this includes gaining control of a permanent with the ability that another player controls.