雀の涙 (suzume no namida)

Literally: Sparrow's tears

Example: “ボーナスは雀の涙ほどだった。” — The bonus was a drop in the bucket.

English equivalent: Drop in the bucket

Origin: Built on simple, imaginative logic rather than any documented historical event: a sparrow measures only about 14 centimeters, among the smallest and most familiar wild birds in everyday Japanese life, so whatever tears such a tiny creature might shed would necessarily be a vanishingly small amount — visible in the imagination, perhaps, but negligible in any practical sense. The phrase is already well established in Edo-period writing, suggesting it was already old and familiar by the time it began appearing regularly in print, and the sparrow's constant, everyday presence around homes and farms likely made it an intuitive, immediately understandable choice for describing an amount too small to matter.