Finding out the plagiarism, Komachi attempted to prove the true authorship of her work and therefore poured some water from her tsunohanzo onto a page on which the waka in question had been handwritten with Chinese ink by Kuronushi, so that the letters were washed out, thereby exposing Kuronushi's guilt.
その際、小町がそれを自分のものと証明するために歌の書かれた紙を角盥漱で洗ったところ、文字が流れ落ちて黒主の罪が明らかになったという。