Perfective gerund for prior action

1. Formation
The perfective gerund (answering the question что сделав?) is typically formed from the past tense stem of a perfective verb:

• -в: The most common suffix for past tense stems ending in a vowel. Example: прочита-л → прочита-в (having read).
• -вши-сь / -ши-сь: Used for reflexive verbs. Example: умыл-ся → умы-вши-сь (having washed oneself), спас-ся → спас-ши-сь (having saved oneself).
• -ши: The standard morphological suffix for verbs whose past tense stem ends in a consonant. Example: спас → спасши, вырос → выросши.
• -я / -а: A variant suffix derived from the future tense stem, which has become the preferred form for specific groups of verbs, most notably verbs of motion. Example: прийти → придут → придя, уйти → уйдут → уйдя, принести → принесут → принеся, прочесть → прочтут → прочтя. Note that the suffix -я-сь is simply the standard -я suffix combined with the reflexive postfix -сь (e.g., возвратят-ся → возврат-я-сь).

Note on Verbs in -ну-: Verbs with the suffix -ну- (e.g., привыкнуть, исчезнуть) form the perfective gerund by keeping the -ну- and adding -в (e.g., привыкнув, исчезнув), even though their past tense often drops the -ну-.
Note on Verbs in -ереть: For verbs ending in -ереть (e.g., умереть, запереть), the primary normative standard uses the -в suffix (умерев, заперев), while forms with -ши (умерши, заперши) are permissible variants.
Note on Variant Forms: The form увидев is the standard modern literary norm, while увидя is an older, poetic, or colloquial variant that learners might encounter. However, forms like привыкши are considered substandard; the standard form is привыкнув.

2. Usage and Meaning
The gerund typically describes a prior action that is already complete when the main verb occurs. While usually referring to the past, it can also refer to the future if the main verb is in the perfective future (e.g., 'Having finished the work, I will call you'). Additionally, perfective gerunds are frequently used with present tense imperfective verbs to describe habitual or repeated sequences (e.g., Вернувшись домой, он всегда включает телевизор).

3. Resultative State
Perfective gerunds are heavily used to describe a resultative state that is simultaneous with the main verb (e.g., Он сидел, закрыв глаза - He sat with his eyes closed).

4. The Same-Subject Rule
Crucially, the logical subject performing the gerund action must be the same as the subject of the main verb. However, the gerund can also be used in impersonal sentences with an infinitive where there is no explicit grammatical subject (e.g., Закончив работу, нужно выключить компьютер). Warning: Using a gerund in an impersonal sentence with a dative subject (e.g., мне) is considered incorrect in strict/formal normative grammar, although it is frequently used by native speakers in modern Russian. If the subjects are different, you must use a subordinate clause with когда or после того как.

5. Negation
To form the negative of a gerund, the negative particle не is written separately from the gerund (e.g., не прочитав, не сделав).

6. Punctuation
In Russian, gerunds and gerundial phrases (деепричастные обороты) must almost always be set off by commas, regardless of their position in the sentence.

7. Register
This form is highly characteristic of written Russian, including literature, news, and academic texts. In casual speech, Russians prefer using two finite verbs connected by 'and' (perfective sequence) or a time clause.