I am confused as to what historical present tense is, when it is used, etc

Question

I understand that historical present tense is basically a tense that uses

"present tense to describe past events/actions more vividly and lively..." - Chocolate

Doing my own research into possible examples of historical present tense has only left me more confused as to what it is, how to use it, how to recognize it, the rules governing its use, etc.

1. How can I tell if a sentence (or part of a sentence) in Japanese is written using the historical present tense?

2. How can I tell if a sentence is NOT written in historical present tense?

3. In historical present tense written in Japanese, are the past events written with past tense while the rest of the sentence is written in present tense?

4. Should I attempt to translate the historical tense and put everything into present tense when translating from Japanese to another language?

4.a. What tense do I use for the actual events when I don't know what said events tense type is? (うなずいて in the below example)

曖昧{あいまい}にうなずいてから, あと二人, 部屋の中に誰かいるのに気がついた.

Examples claiming to use historical present tense: ["気づく"][1] <- here, [this stack question][2], and [this one][3] too, oh, and [here][4]

(If I had enough points I would create and use a historical-tense tag for this, but as I do not have enough right now, I am using the 'interpretation' tag for the mean time.) [1]: Understanding a sentence 〜声が誰のものか [2]: How does present tense work in Japanese narration? [3]: Negative present endings translated as past tense [4]: How is "と" being used in these two sentences: 「ふりむくと、こどもたちが...」「トンネルをつくろうっと。」

Answer 1

1. Context. See the example below.
2. Context.
3. Historical present happens on per-sentence basis (i.e., it's about the tense of the main verb usually at the end of each sentence). When you see mixed tense within one sentence, that's probably related to relative tense.
4. Historical present happens in English novels, but it's probably more common in Japanese novels. If you feel there are too much historical present in Japanese text you're trying to translate, you may want to translate some of the sentences into English using past tense.

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Historical present is something shown below (pink). See how this author switched tense very frequently at the end of each sentence. Also note that the verbs in subordinate clauses (green) are not related to historical present; they have nothing to do with "vividness".