1. He went up.

2. Up he went.
3. Up went he.

4. The princess went up.
5. Up the princess went.
6. Up went the princess.

(Which ones are grammatically correct?)

All could be used, depending on the context.

#s 3 and 5 are awkward, though.

7-2

All six sentences are grammatically correct, but their structures differ and depend on the desired emphasis in the sentence.

1. "He went up."
This is a straightforward sentence in the Subject-Verb-Object (SVO) word order, which is the most common structure in English.

2. "Up he went."
This sentence uses a more poetic or dramatic structure called an inversion. Instead of the typical SVO order, the subject (he) and adverb (up) swap places. This inversion can be used to create emphasis or a sense of anticipation.

3. "Up went he."
Similar to sentence 2, this sentence also uses inversion but with a slightly different word order. It is less common in modern English but can still be used for poetic or archaic effects.

4. "The princess went up."
Like sentence 1, this sentence follows the SVO word order and is grammatically correct.

5. "Up the princess went."
This sentence, using a preposition (up) before the subject (the princess), is another example of inversion. It gives a poetic or dramatic effect similar to sentence 2.

6. "Up went the princess."
This sentence is constructed like sentence 3, using inversion starting with the adverb "up" and then the subject (the princess). It creates a similar poetic or archaic tone.

In summary, sentences 1, 2, 3, 4, 5, and 6 are all grammatically correct, but their structures vary in terms of regular word order (SVO) and inversions that can be used for stylistic or rhetorical purposes.