Russian Prepositional Case: Endings, в vs на, and о

The prepositional case is the one Russian case with no other job. The genitive also marks possession and absence, the dative marks the recipient and the person who feels something, and the instrumental marks the tool and the company. The prepositional does none of that. It turns up after four prepositions, в, на, о and при (plus по in a few formal phrases such as по приезде, on arrival), and nowhere else.

That is why the Russian cases chart recommends it straight after the nominative and accusative. The trigger is always visible, the endings are the most uniform of the six, and you will need it in your first week: Где ты? В шко́ле. Where are you? At school.

The endings: mostly -е

In the singular, nearly every noun takes -е, whatever its gender:

The stress is marked in the transliteration. Notice в itself: before a voiceless consonant such as к or ш it is pronounced f, so в шко́ле sounds like f shkólye and в кни́ге like f knígye. An unstressed о sounds like a, which is why го́род gives góradye. The spelling does not change; only the sound does.

Two groups take -и instead (and so do the rarer masculine nouns in -ий):

The plural is simpler still. Every gender takes -ах, or -ях after a soft stem: в домах (in the houses), в книгах (in the books), на столах (on the tables). If you can tell a hard stem from a soft one, you can form any prepositional plural in the language.

В and на: where the real difficulty is

Both prepositions take the prepositional when they mean location, so the case is never the problem. The choice between them is.

В means in: inside something with walls, edges or borders.

Я живу́ в го́роде. - I live in the city.

Ма́ма в ко́мнате. - Mum is in the room.

На means on a surface, and also at open spaces, events and a set of places that simply have to be learned:

Кни́га на столе́. - The book is on the table.

Она́ на рабо́те. - She is at work.

The places that take на are the part to memorise, because English gives you no clue:

Кино́ never changes its ending at all. It is one of a handful of borrowed nouns ending in -о that do not decline, which makes it the easiest word on this page.

The logic behind на is partly historical and partly about openness: a street and a seaside have no roof, a party and a job are events rather than buildings. Take the logic as a memory aid rather than a rule, because it does not explain every case. Learn each place with its preposition, as a unit, the first time you meet it.

Где or куда: the question tells you the case

В and на do two jobs, and the question word separates them. Где? (where?) asks for a location, and the answer is in the prepositional. Куда́? (where to?) asks for a direction, and the answer is in the accusative:

Где ты? В шко́ле. - Where are you? At school. (prepositional)

Куда́ ты идёшь? В шко́лу. - Where are you going? To school. (accusative)

English uses where for both and lets the verb carry the difference. Russian marks it twice, once in the question and again in the ending. If you are unsure which ending a sentence needs, ask yourself which question it answers. That one test settles almost every in-or-into decision you will face.

О: talking and thinking about

The other big use is о, about. Any verb of talking, thinking, reading, writing or dreaming takes о with the prepositional for its topic:

Мы говори́м о кни́ге. - We are talking about the book.

Я ду́маю о тебе́. - I am thinking about you.

О has two longer forms for pronunciation's sake. Before a vowel sound it becomes об: об э́том (about this), об отце (about father). Before мне it becomes о́бо: о́бо мне (about me). The case after all three is the same.

With pronouns, the prepositional forms are о́бо мне, о тебе́, о нём, о ней, о нас, о вас and о них. The third-person forms start with н- because the prepositional always follows a preposition; the personal pronouns article explains the rule.

The fourth preposition, при, means in the presence of or attached to, and is formal enough that you can leave it until you read it in the wild.

Where is everyone? The case in a real exchange

Here is the prepositional doing the job it does most, in the kind of exchange you will have in your first week:

Где ма́ма? - Where is Mum?

Она́ до́ма. - She is at home.

А па́па? - And Dad?

Он на рабо́те. - He is at work.

А где ключ? - And where is the key?

На столе́, в ко́мнате. - On the table, in the room.

The odd one out is до́ма. It means at home, it answers где, and it has no preposition at all, because it is an old frozen form rather than a live prepositional. В до́ме exists too, but it means in the house, the building, not at home. Its partner for direction is домо́й (home, homewards), so the где and куда́ split still holds; it just uses two fixed words instead of an ending.

Time works the same way as place for a few common phrases: в э́том году́ (this year), в про́шлом году́ (last year), на э́той неде́ле (this week). The last one takes на, not в, and there is no logic to recover: learn it as a phrase.

The -у locative: a leftover seventh case

About a hundred masculine nouns, most of them short and common, take a stressed -у instead of -е when they mean location after в or на:

на полу́ - on the floor

в э́том году́ - this year

в ле́су, в саду́, в углу́ - in the forest, in the garden, in the corner

This is the remains of an old locative case that the prepositional mostly swallowed. It only survives after в and на: after о, the same nouns go back to -е. Do not try to predict which nouns have it. Learn the dozen common ones as fixed phrases, the way you would learn at home or in bed in English.

Adjectives in the prepositional

An adjective in front of the noun agrees with it, taking -ом for masculine and neuter and -ой for feminine (-ем and -ей on soft stems): в но́вом до́ме (in the new house), в большо́м го́роде (in a big city), в э́той ко́мнате (in this room). The endings are more regular than the noun endings, and Russian adjectives sets them out across all six cases.

Mistakes English speakers make

1. Using the prepositional for motion. Я иду́ в шко́ле means I am walking about inside the school, not I am going to school; going somewhere needs the accusative, в шко́лу. If the sentence answers куда́?, it is not the prepositional.
2. Choosing в where Russian says на. In the street is на у́лице, not в, and at work is на рабо́те. The English preposition is no guide, so learn the place and its preposition together.
3. Putting -е on a soft-sign feminine noun. It is в жи́зни, not жизне. The soft-sign feminine nouns take -и in this case, and so does anything ending in -ия.
4. Leaving о bare before a vowel. Об э́том, not о этом. It is a small thing and a Russian ear catches it every time.
5. Missing the stressed -у. На полу́, not на поле, which is a different word altogether (on a field).

What to do next

Learn the -е ending today, because it covers most nouns you know, then learn five places that take на as fixed phrases: на рабо́те, на у́лице, на вечери́нке, на мо́ре, на полу́. After that, practise asking yourself где or куда́ every time you say where something is. The next case in the learning order is the genitive, which marks possession and absence, and the Russian course drills the prepositional in its third chapter.