Ни один: not one, no one, not a single one
Among the many things I get wrong in Russian, properly using ни and не (not) is right up there at the top of the list. In spoken language, I can get away with a vowel sound somewhere between the short “е” of не and the long “и” of ни and pretend that any perceived incorrect usage is actually just my unfortunate accent.
But these adolescent tricks don’t work on the printed page. And so I’ve been struggling to understand when to use ни and не.
I think I’ve almost got it. Ни is used in some standard expressions that are fairly easy to memorize. The rest of the time, ни is не with an attitude.
Let’s start with the so-called easy stuff. Ни is used in “neither nor” expressions, such as ни жив ни мёртв (neither dead nor alive); ни рыба ни мясо (neither fish nor foul); ни то ни сё (neither this nor that), ни с того ни с сего (all of a sudden, literally “neither due to this nor that”). Я ни за, ни против. (I’m not for it or against it.) Ни хлеба, ни зрелищ народ не получил. (The people got neither bread nor circuses.)
Ни makes an appearance as a stronger version of не in a few standard adamant commands: Ни с места! (Don’t move an inch, -literally “not from that spot”). Ни шагу назад! (Never retreat, literally, “not a step back”).
When you use the words один (one) or единый (a single), or when they are implied, you should use ни and not не. Она ни разу не позвонила. (She didn’t call even once.) У меня в кармане не было ни рубля. (I didn’t have a single ruble in my pocket.) Ни один человек не пришёл на вечеринку. (Not a single person came to the party.) Here you need to listen or read carefully to distinguish between ни and не, since the phrase не один человек пришёл на вечеринку means the opposite: Many people (that is, “not just one person”) came to the party.
Then there are the confusing cases involving ни when it looks like nobody and nothing, but it’s actually anybody and anything. When ни is used with pronouns and adverbs like кто (who), что (what), какой (which), как (how), куда (where) and сколько (how much), it magically turns things into their opposites. Кто ни придёт, мама бежит ставить самовар. (No matter who comes, my mother runs to put on the samovar.) Где бы он ни появился, всюду его узнают. (Wherever he showed up, everyone knew him.)
The really tricky stuff is the usage of ни that is an “intense negation.”
This drives Russian school children — and foreigners — crazy. When is it intense enough to use ни? Here’s an example: Дайте мне рукопись. Клянусь, я не изменю в ней ни слова. (Give me the manuscript. I swear I won’t change a single word.) And here’s a poetic excerpt: Ни одна звезда не озаряла трудный путь. (Not a single star illuminated his difficult path.)
My rule of thumb is: If you can use the phrase “not a single” in English, go for ни in Russian.
And if you’re not sure?
Ask native Russian speakers. And wait while they look it up.