『JTF日本語標準スタイルガイド（翻訳用）』 is a style guide for translators putting non-literary material into Japanese. Compiled by the JTF Style Guide Committee to help translators make informed decisions and stay consistent,it first appeared on January 30, 2012.
Thinking the information might also be useful for translation clients who do not read Japanese, JAT volunteers (Fred Uleman, Syra Morii and Emily Shibata-Sato) translated version 1.2 for free distribution on the JAT and JTF websites.
Both the original Japanese and the English translation ("Style Guide for Translators Working into Japanese") can be downloaded from here