"Single drop of red" (Wuxia) I have this only via oral tradition, but wanted to ask about it here b/c I assume this is where the Chinese scholars are.

Where does this phrase appear in the Chinese literary tradition, what are the range of possible translations, and hidden meanings that would be lost in translation?

(For background, &quot;single drop of red&quot; is an ideal of Chinese swordplay, whereby the knight errant dispatches an opponent with a single thrust of the minimum necessary depth, leaving only a small wound, presumable with little bleeding.)
The term 一點紅 you are referring to is an assassin/ swordsman called '中原一點紅' in a Chinese Martial art novel 《楚留香》 by 古龍.
His signature move is a sword-thrust so precise that it only leaves behind a tiny wound, looks like a red dot on his opponent's forehead.
We don't know his true name. He was only known as '中原一點紅' in the novel
It is fictional, not a real martial art term
Notices:

In general, 一點紅 means 'the only female among a group of males'. It came from the Chinese expression '萬綠叢中一點紅' (a single red dot in a greenfield). Example: &quot;麗莎是我們出版社的一點紅&quot; means &quot;Lisa is the one red dot (only female member) in our publishing house&quot;

And 萬綠叢中一點紅 came from the poem 《咏石榴花》. (a poem about pomegranate flower) by 王安石（1021-12-18 ～ 1086-5-21）

今朝五月正清和，榴花詩句入禪那。


濃綠萬枝紅一點，動人春色不須多。


紅一點 refers to a single pomegranate flower among trees full of green leaves, a sign of early spring.


一點紅 is also the name of a plant that is used in traditional Chinese medicine