山椒は小粒でもぴりりと辛い
(Sanshou wa kotsubu de mo piriri to karai;
“Japanese peppers are small but painfully spicy”)

Definition:

This saying metaphorically describes someone who is physically small, but still formidable due to well-honed talents and a fierce spirit, surprising strength, or other exceptional qualities. Don’t underestimate someone just because they’re small.

Breakdown:

We begin with the noun 山椒 (sanshou), a close relative of the more famous Sichuan pepper, marked as the topic of discussion by the particle は (wa). The comment on this topic begins with the noun 粒 (tsubu), “grain,” “particle,” compounded the prefix-noun 小 (ko), “small.” This is followed by conjunction でも (demo), “but,” “although.” The phrase that follows begins with onomatopoetic adverb ぴりり (piriri), “tingling,” “stinging.” This is followed by the particle と (to) in its function of marking the adverbial use of onomatopoeia. Finally, we have the adjective 辛い (karai), spicy,” in conclusive form.

Notes:

山椒 may also be read with a short final vowel, as sansho, although in my sources this appears to be the less-common rendition.

A related saying points out that while a needle is small, it’s not something you can just swallow. Yikes. That said, the peppercorn version describes a level of ability that’s not to be sneezed at; it would be an error to use it to describe something harmful or dangerous despite its small size.

Example sentence:

「あの子だったら、大臣や偉人さえ説得できるらしい。山椒は小粒でもぴりりと辛いもんね」

(“Ano ko dattara, daijin ya ijin sae settoku dekiru rashii. Sanshou wa kotsubu demo piriri to karai mon ne.”)

[“They say that she can even turn the great and the powerful to her cause. ‘Even the smallest person can change the course of the future,’ eh?”]