expression, ichidan verb
ignite; set fire to
Literal act of lighting something on fire, such as a candle, stove, or building.
彼はマッチでろうそくに火をつけた。
He lit the candle with a match.
放火犯が倉庫に火をつけた。
The arsonist set fire to the warehouse.
expression, ichidan verb
Figurative use: to cause a conflict, controversy, or strong emotion to erupt. Often used with nouns like 論争 (controversy) or 感情 (emotions).
彼の一言が大論争に火をつけた。
His single remark sparked a huge controversy.
その事件は国民の怒りに火をつけた。
The incident inflamed public anger.