Grammar 18--Instrumental Case

To Identify the Instrument of the Action

The primary use of the instrumental case without a preposition is to indicate the instrument, equipment or means by which the action in the sentence is performed. For example:

Он писа́л карандашо́м.

He wrote using a pencil.

Они́ прие́хали маши́ной.

They arrived by car.

Анна откры́ла ба́нку ножо́м.

Anna opened the can with a knife.

Шпио́н говори́л шёпотом.

The spy spoke in a whisper.

А́нна шла по́лем.

Anna was walking by way of the field.

The instrumental is often used with reflexive verbs:

Я занима́юсь ру́сским языко́м.

I am studying Russian.

(Lit: “I am occupying myself with the Russian tongue.”)

Я по́льзуюсь словарём.

I am making use of a dictionary.

Он интересу́ется э́той кни́гой.

He is interested by this book.

To Indicate a Role or Condition

Another important use of the instrumental case (again without a preposition) is to name a role in which someone or something serves. For example, it can be used with быть (to be) in the past or future:

А́нна была́ студе́нтом.

Anna was a college student.

Он был больны́м.

He was a sick man.

Когда́ я вырасту́ я бу́ду врачо́м.

When I grow up will be a doctor.

Do not try to use the instrumental case to say that someone presently is something. Use the nominative:

Он врач.

He is a doctor.

Also do not use the instrumental case to indicate a condition which has always been and cannot change. Compare the following:

Вашингто́н был америка́нец.

Washington was an American. (all his life, nominative)

Вашингто́н был президе́нтом.

Washington was president. (for eight years, instrumental)

Certain verbs must always be used with the instrumental case because their meaning indicates a change of role or condition or service in a particular capacity:

А́нна ста́ла ма́терью.

Anna became a mother.

Сюза́нна служи́ла учи́телем.

Susanna served as a teacher.

Это послу́жит приме́ром.

That will serve as an example.

Он явля́ется террори́стом.

He is being a terrorist.

With Prepositions

The instrumental case is used with certain prepositions to indicate static location:

с

with

над

over

под

under

ме́жду

between

пе́ред

in front of

Translating from English

Be careful with the preposition “с”. Do not use when identifying the instrument of an action (as described above), even where you would say “with” in English. If you do, the instrument will cease to be an instrument and will become a companion, often in defiance of common sense:

А́нна откры́ла ба́нку с ножо́м.

Anna opened the can with the knife on it.

Or maybe: Anna and the knife opened the can.

As you see from this example, inappropriate use of “с” creates weird unintended meaning.