By their refrigerated, long-distance-shipped fruits?

悪事千里を走る
(Akuji senri wo hashiru; “Bad deeds run a thousand leagues”)

Definition:

When you do bad things, the rumors spread rapidly throughout society. News of evildoing soon reaches a distance of a thousand ri. There’s an implicit contrast with news of good deeds, which spreads much less far and less quickly, but in either case the lesson is the same: watch your actions carefully lest you gain a reputation as a villain.

Breakdown:

We begin with compound noun 悪事 (akuji), literally “bad thing(s).” Any particle is elided, although one could make a case for topic-marker は (wa) or subject-marker が (ga) here. Instead, we move to number-noun 千里 (senri), “one thousand ri.” And this distance is marked by the particle を (wo) as the object of the verb 走る (hashiru), “to run,” appearing here in sentence-final form.

Notes:

This saying is derived from a 10th Century CE Chinese text known as the Beimeng Suoyan (北夢瑣言, in Japanese Hokumu sagen).

Some versions of this saying use 行く (iku or, more commonly, yuku), “to go,” in place of 走る. In the original usage, the akuji phrase is preceded by one about how – in Japanese rendition – 好事門を出でず (kouji mon wo idezu): good deeds don’t even make it out the gate.

Apparently some people interpret this saying as saying that bad deeds are copied far and wide rather than known. While such usage would be no less topical now, as I write this post, it’s still considered an error.

Example sentence:

「よせよ、ツイッターの発明の前ですら悪事千里を走っていたんだ。今なんてなおさらだよ。そんな胡散臭い計画、参加したくないって言っただろ」

(“Yose yo, Tsuittaa no hatsumei no mae de sura akuji senri wo hashitte itanda. Ima nante nao sara da yo. Sonna usan kusai keikaku, sanka shitakunaitte itta daro.”)

[“Cut it out! Even before Twitter was invented, ‘bad deeds could run a thousand leagues.’ All the more so nowadays. I already said I didn’t want to be involved in such a fishy scheme.”]