Lightning and flint-spark. Real idiom for something over in an instant.

What a Japanese person actually thinks
Punchy and slightly sporty. Common in commentary and in martial-arts writing. Reads as energetic rather than deep.

Meaning

Literally: lightning + flash + stone + fire
Actually: Blindingly fast — the flash of lightning, the spark struck off flint. Used for speed of action or decision.

Scores

Naturalness●●●●●

Established idiom.

Coolness●●●●●

Four characters carrying two separate images of light. Visually strong, meaning is straightforward.

Watch out

Nothing embarrassing lurking in here.

On skin

電光石火

Orientation: vertical

Bold Mincho or brush, vertical.