How to change the font of Japanese characters

Question

Im currently working on a file where I need to display some Kanji in the middle of some English text. For this I created a new environment with the CJKuft8 package, according to this post

\usepackage{CJKutf8}
\newcommand{\japanese}[1]{\begin{CJK}{UTF8}{ipxm}#1\end{CJK}}

This works still just fine, but I have a slight problem with it: I'd like to change the font in which the Kanji are displayed (only the Japanese characters, not the rest of the text), but I don't know how to achieve that.

I found this answer, but it suggests using XeLaTeX, with which I am not familiar. Since I wanted to use Source Han Code JP, which is a OpenType Source font, I found also this question here, but there LuaLaTex was suggested.

After all of this I'm somewhat confused what the best strategy is to achieve my goal. Should I switch to XeLaTeX or LuaLaTex? Or can I even achieve my goal without changing to much (currently running pdflatex)?

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Further Information: If possible I'd like to avoid having to switch to XeLaTeX or LuaLaTeX since the file is already quite big, has a lot of imported packages and I'm not familiar what is compatible with what.

Answer 1

If you stick to pdfLaTeX, you have to convert an arbitrary OpenType/TrueType font to a Type1 font and create a map file; that requires a lot of works and special knowledge about "how font is handled by TeX". Usually, the process cannot be completed automatically, and it's too difficult for beginners. IPAex font (= you are using that in the above MWE as "ipxm") is currently the only example which is contributed by a Japanese TeXnician, so I strongly recommend one of the followings:

1. use "ipxm" with pdfLaTeX.
2. switch to LuaLaTeX. (LuaLaTeX is upper-compatible with pdfLaTeX in most cases)

LuaLaTeX can handle OpenType/TrueType font natively. Here is a simple example of using Japanese fonts. (Here I used \font primitive directly but another LaTeX-like solution would be possible)

\documentclass{article}
\usepackage{fontspec}
\font\ipaexm=IPAexMincho % PSName of an arbitrary font
\font\ipaexg=IPAexGothic
\begin{document}
Type your content here.
{\ipaexm 日本語}
{\ipaexg 日本語}
\end{document}

Answer 2

Here’s an alternative MWE using babel. Unfortunately, there’s an incompatibility between babel 3.22, which loads all Japanese fonts with Script=Japanese, and fontspec 2.6h, which expects Script=Kana. I’ve provided a workaround. (Also, Source Han Code JP doesn’t support the Japanese-language OpenType feature, which is odd but probably harmless.)

Since you wanted to use Source Han Code JP, an OpenType font, this document compiles with XeLaTeX (and appears to work with LuaLaTeX, although as of 2018, its support for non-European scripts is more rudimentary.)

\documentclass[varwidth, preview]{standalone}
\usepackage{fontspec}
\usepackage[english]{babel}

% The Script= setting is broken for Japanese as of August 2018.
% Workaround:
\babelprovide[import=ja, script=Kana]{japanese}

\defaultfontfeatures{Scale=MatchUppercase, Ligatures=TeX}

\babelfont{rm}[
  Scale = 1.0,
  Ligatures={Common, TeX}]{Source Serif Pro}
\babelfont{sf}[Ligatures={Common, TeX}]{Source Sans Pro}
\babelfont{tt}{Source Code Pro}

% Font available at: https://github.com/adobe-fonts/source-han-code-jp
\babelfont[japanese]{rm}[
  Ligatures = {Discretionary, TeX},
  UprightFont = *-Regular ,
  BoldFont = *-Bold ,
  ItalicFont = *-RegularIt ,
  BoldItalicFont = *-BoldIt ,
  Extension = .otf ]{SourceHanCodeJP}

\begin{document}
Text in \foreignlanguage{japanese}{日本語}.
\end{document}