Disclaimer: I've never done any professional Japanese to English translation before
I found the following in The Routledge Course in Japanese Translation by Yoko Hasegawa. Note that ST stands for source text and TT stands for translated text.
Between Japanese and English, an adjustment that is frequently called
for concerns paragraph breaks. Compared to Japanese, English writing
has significantly fewer breaks (K. Inoue 2004: 95); conversely,
Japanese writing utilizes frequent line breaks. One may even encounter
Japanese texts that place a line break after every kuten 句点 (｡). This
is due to the fact that the concept of paragraph has not been clearly
established in Japanese writing (Hojo 2004: 41). Let us examine
whether there is a discrepancy between STs and TTs in regard to
paragraphing. The following table compares the number of paragraphs in
the first section or chapter of the STs with their corresponding TTs.
|Alice’s Adventures in Wonderland
|A Pale View of Hills
|Saving Private Ryan
|The Cop and the Anthem
|The Moon and Sixpence
|The Selfish Gene
Clearly shown by this table is the fact that paragraph breaks are
maintained in English-to-Japanese translation, whereas they are likely
to be changed in Japanese-to-English translation. Moreover, when
paragraphs are adjusted, English TTs invariably have fewer paragraphs.
Although we do not investigate how paragraphs are combined in English
TTs, Japanese-to-English translators should be aware that such an
adjustment might be called for in order to produce quality TTs. (For
an excellent discussion of paragraph adjustment in translation, see
Hojo 2004: 41–59.)
References mentioned in the excerpt:
Inoue, Kazuma 井上一馬. 2004. Inoue Kazuma no hon’yaku kyDshitsu 井上一馬の
翻訳教室. Chikuma Shobo
Hojo, Fumio 北條文緒. 2004. Hon’yaku to ibunka – Gensaku tono “zure” ga
kataru mono 翻訳と異文化―原作との<ずれ>が語るもの. Misuzu Shobo.