When the Japanese delegation appears in The Difference Engine, it's not really a surprise. (Oh yeah, I'm going to assume that anyone who wants to read it already has — consider this a spoiler warning.) It's not a surprise, but it is a bit disappointing that Gibson and Sterling couldn't think of anything more interesting for them to do than "study the technologically advanced West, just like in our timeline." This is only partially made up for by the sly joke of having one of them deliver the final, killing blow in the story proper.

One thing about the Japanese delegation, though — they speak very good English. Apart from the obligatory r/l thing, their English is as regular and fluent as, say, Rorschach's. Large vocabulary, good grasp of clause structure, tense, and aspect, but a general absence of articles and tendency to pro-drop.

Mori smiled, pleased. "Odious custom of rude and savage age. This is good to be rid of, Oriphant-san. This is modern day."

Even this, though, is more disfluency than you typically see in records of Japanese English in documents and fiction from and about that time. I don't know if this is just confirmation bias, but my impression is that characters (fictional or otherwise) are assigned either over-the-top pidgin or Churchillian oratory, with very few examples in between. I suppose a lot of this is editorial assistance, at both the primary and secondary source, but still, it's a notable absence.

Anyway, this is my roundabout way of introducing this letter I found in Miyanaga Takashi 宮永孝's Bakumatsu ken'ō shisetsu dan 幕末遣欧使節団 ("The Bakumatsu Embassy to Europe"), from Fukuzawa Yukichi 福沢諭吉 (for it is he) to Léon de Rosny. Sic! throughout:

20. Oct. 1862 Lissabon

Dear friend 羅尼江

How was my gladness, when we arrived at Lissabon. I have received at first the letter from my best Europesh friend M. Leon de Rosny. I am very much obliged for your kindness and I see you are not only the good friend of me but an hearty lover of Japan. I wish and can assure you will keep always the same feelings.

The interesting news from Japan stated in your letter I have read withe much thanks for your troubles, now I wish you will be so kind in the future also to translate with the English language and send them to me, because, you know, I am not able yet to read the Franch and in Japan none understands it very well, thouhg there are any pupils of the Franch language. I know it will makes you much trouble some but this trouble someness would not last so long, because I am now beginning to learn the Franch and after some times I will be able to read it myself.

We have had very bad wether during the voyage from Roc efo rtf to Lissabon where we have arrived at 16th of Oct. Now we have finished all our business and will leave here 24th or 25th of said month. Farewell my best friend! I will never forget you in all my life. I have the honour to be

   your upright friend

      Foucousawa Youkichy

         福沢諭吉

Dr Mitskuri, Matsky, etc, etc, etc, send their best compliments to you.

十八六二年十月二十日　リスボンにて

親愛なる羅尼君へ

Miyanagi observes that proper nouns "Europesh," "Franch," and "Lissabon" probably slipped in to Fukuzawa's English from Dutch. Also on the continental tip, observe that Fukuzawa uses a French romanization of his name — makes sense, given who he's writing to. (Nation-specific romanizations of names in this period, before Hepburn became so universal, are an intriguing topic all on their own.)

I was particularly struck by Fukuzawa's "there are any pupils of the French language" (non-grammatical irregularities corrected). I have met several adults in Japan who used forms like this, despite being very fluent and confident in their English. Logically, it makes sense: if the negative answer to "Are there any pupils of the French language in Japan" is "There are not any pupils...", then the positive answer should be the same minus the "not", right? "There are any pupils of the French language in Japan." It's not immediately obvious that "any" can't be used in the positive version of the statement. (Related: "I have ever been to France" as the opposite of "I have never been to France.")

Also note that Fukuzawa tends to use the perfect where he wants the simple past ("I have received at first the letter," "we have arrived at 16th of Oct"), and generally exhibits wide knowledge but shaky analysis of how certain corners of the English language work ("trouble someness", "after some times"). Seeing this sort of thing in print comforts me because, of course, I am prone to similar errors in Japanese.

Miyanaga's book also includes a letter to de Rosny from Terashima (then Matsuki) Munenori, which I won't quote in full but which does contain a memorable description of their passage to Lisbon: "we ware moved day & night like a pendulum & I saw nobody which was not seasick."