白纸写黑字

Traditional (Taiwan): 白紙寫黑字

báizhǐxiěhēizi ㄅㄞˊ ㄓˇ ㄒㄧㄝˇ ㄏㄟ ˙ㄗ

    • in black and white
    • in writing and undeniable

Character by character

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
black characters written on white paper
Meaning
A less usual form of 白纸黑字: it's in writing and can't be denied.

Sources