Теперь я часто играю в шахматы с братом по вечерам.

Both теперь and сейчас can translate as now, but they’re not completely interchangeable.

• теперь usually means now, from this time on, often contrasting the present with the past.

  • Implies a change of situation or a new habit:
    
    • Раньше я не играл в шахматы, а теперь играю.
      Before, I didn’t play chess, but now I do.

• сейчас is more neutral right now / at the moment. It doesn’t automatically suggest a change from before.

  • Сейчас я играю в шахматы.
    I am playing chess now (at this moment).

In your sentence, теперь fits because it describes a new regular habit that started at some point and is true from now on.

Часто is an adverb, meaning often. In Russian, adverbs:

• Do not change for gender, number, or case.
• Do not agree with the subject or the verb.
• Usually answer how?, how often?, in what way?, etc.

So:

• я часто играю – I often play
• она часто играет – she often plays

Часто stays the same in both cases, because it modifies the action (играю/играет), not the person.

Yes, Russian word order is flexible, and adverbs like часто can move to change emphasis slightly:

• Теперь я часто играю в шахматы с братом по вечерам.
  Neutral: just saying you now often play chess with your brother in the evenings.

• Теперь я играю в шахматы с братом часто по вечерам.
  Sounds a bit clumsy; not wrong, but less natural.

• Теперь я по вечерам часто играю в шахматы с братом.
  Emphasizes the time frame: Now, in the evenings, I often play...

The most natural options here are:

• Теперь я часто играю в шахматы с братом по вечерам.
• Теперь я по вечерам часто играю в шахматы с братом.

The meaning is almost the same; you’re just slightly shifting what you highlight.

In Russian, with most games and many sports, the verb играть usually takes the preposition в plus the accusative case:

• играть в шахматы – to play chess
• играть в футбол – to play football/soccer
• играть в карты – to play cards

So the basic pattern is:

• играть в + [game/sport, accusative]

You do not normally say играть шахматы; that sounds incorrect or at least foreign.

Шахматы is:

• grammatically plural (it always appears as a plural word in normal use),
• in the accusative plural here, governed by в after играть.

For inanimate plural nouns, the form of the accusative is the same as the nominative:

• Nominative plural: шахматы
• Accusative plural: шахматы

So it looks like the nominative, but syntactically it is accusative because of играть в.

Russian uses different prepositions with играть depending on what you play:

• играть в

  • accusative – games and many sports
  • играть в шахматы – to play chess
  • играть в теннис – to play tennis

• играть на

  • prepositional – musical instruments
  • играть на гитаре – to play the guitar
  • играть на пианино – to play the piano

This is just a stable pattern you have to remember:

• играть в + game/sport
• играть на + instrument

The preposition с meaning with normally takes the instrumental case:

• с кем? – with whom?
• с чем? – with what?

Брат (brother) in the instrumental singular is братом. So:

• с братом = with (my) brother

The sentence doesn’t say my, but in Russian, with close family members, you often omit the possessive when context is clear. It usually implies my unless something else is specified:

• играю с братом – I play with (my) brother
• играю с его братом – I play with his brother

For a masculine noun like брат, the instrumental singular is usually formed with -ом (after a hard consonant):

• брат → братом
• стол → столом
• дом → домом

So:

• Nominative: брат (who? what?)
• Instrumental: братом (with whom? by whom? with what?)

You need the instrumental here because of с = with.

По вечерам literally is by evenings / along evenings, but idiomatically it means:

• in the evenings (as a regular habit), on evenings (habitually).

Grammar:

• вечер – evening (singular nominative)
• Dative plural: вечерам
• по
  • dative plural = по вечерам

Nuance:

• вечером (instrumental singular) – in the evening (one particular evening or a general time of day, more neutral)
• по вечерам – in the evenings (usually / regularly / every evening or many evenings)

Your sentence describes a habitual action, so по вечерам is more natural than вечером.

По вечеру is possible in some contexts, but:

• по вечерам is the very standard way to say in the evenings (regularly).
• по вечеру is much less common, more literary/old-fashioned in this sense, and can sound odd or overly stylistic in everyday speech.

For everyday modern Russian, to express a regular evening habit, use:

• по вечерам – in the evenings (habitually)

The word order is not rigid. You can rearrange parts for emphasis while keeping the same basic meaning:

• Теперь я часто играю в шахматы с братом по вечерам.
  Neutral, as given.

• Я теперь часто играю в шахматы с братом по вечерам.
  Slightly more emphasis on я: As for me, now I often...

• По вечерам я теперь часто играю в шахматы с братом.
  Emphasis on по вечерам (time frame) and теперь (change).

All of these are acceptable. The original word order is very natural and typical.

Russian verbs have aspect: imperfective vs. perfective.

• играть – imperfective: describes processes, repeated actions, habits.
• сыграть / поиграть – perfective: describe single, completed actions or a limited period.

In your sentence, you’re talking about a regular habit:

• Теперь я часто играю в шахматы...
  → I often play chess now (habit, repeated action)

So the imperfective играть is correct.

If you change to сыграть or поиграть, the meaning changes:

• Теперь я сыграю в шахматы с братом по вечерам.
  Sounds like you’re promising/intending to play (completed games), not talking about a general habit.

• Теперь я поиграю в шахматы с братом.
  More like: Now I’ll play chess with my brother for a while (once, for some time).

For habits, stick with the imperfective: играть.

Играть is a regular first‑conjugation verb. Its present tense forms are:

• я играю
• ты играешь
• он/она/оно играет
• мы играем
• вы играете
• они играют

For я, the ending is -ю (after a vowel, often written -ю, pronounced [ю]):

• игра
  • ю → играю

So:

• я играю = I play / I am playing

The -ю here is just the standard first-person singular ending for this verb type.

In Russian, you normally cannot drop subject pronouns the way you can in Spanish or Italian. You usually need to say я.

However, in informal speech, people occasionally omit я if:

• The subject is absolutely clear from context, and
• The sentence follows immediately after mention of я.

Still, the full, correct, and most natural version is:

• Теперь я часто играю в шахматы с братом по вечерам.

Dropping я here, as a standalone sentence, sounds incomplete or stylistically off.

Stress and approximate pronunciation (stressed syllables in caps):

• Теперь – te-PERʹ
• я – ya
• часто – CHA-sta (the second о is reduced, like a)
• играю – ee-GRA-yu
• в – v (very short)
• шахматы – SHAH-mat-y (the last ы is like a hard, central i)
• с – s (very short)
• братом – BRA-tam
• по – pa (unstressed, sounds like pa)
• вечерам – vee-che-RAM

Word stress in Russian is important, because it can change the vowel quality significantly, especially о and е in unstressed positions.